How about we start afresh?
Let us address the OP. The question being “Does art have to be beautiful?”
From the get go I see a problem with the question. Before we can begin to answer it makes sense to outline, as best we can, what is meant by “beauty”. I am not willing to go into definitions of “Art” here (I have taken on the issue of “conceptual art” in another thread dedicated to that aspect of the art world.)
I think we bith agree that art doesn’t have to be “beautiful,” but what do we mean by this? How can we approach this question? What evidence is appropriate? What examples can we give?
We do have multiple studies that show what people find to be “beautiful” to have a very strong correlation to symmetry (this is undeniable), yet at the same time a certain degree of asymmetry, offsetting the perfect geometrical balance (visually or “otherwise” - musically etc.) to produce a subjectively more attractive “harmony.”
So in general “beauty” has a lot to do with concepts like “harmony”, “balance”, “purity”, and “melody.” We understand all music, dance, sculpture, painting and prose in these terms. Obviously there is a counter position, aa antonym to the concept of “beauty” and we coommunicate this idea in opposition to the above mentioned terms with “disharmony”, “discord”, “imbalance”, “impure”, and “cacophany” (which stems from Greek “kakos” in opposition to “kalos”, which sequentially are roughly translated as “bad” and “good”, although “kalos” has a more subtle meaning and translations into English often take on the form “love”.)
People may be driven forward by the ideas taken from Taoism or other sources based more in mysticism (and with good reason.) Within beauty there is ugliness, becasue understanding one requires knowledge of the other (and more direct experience too.) One may even take on thr black and white view in order to “order” the terms in use. So we’re left with the more entropic view of things being in somewhere on the spectrum of order and disorder, and what is called “order” has more in common with beauty than with ugliness, yet contrary to this what is utterly ordered is genric, obiquitious and essentially stale and dead (refer to Oscar Wilde’s point here that I mentioned previously.)
The most curious thing about beauty is we silly humans have the bias of logical assumption (I say “logical” ironically here because we often confuse base intuition with logic.) To explain further, I simply mean one would expect “perfection” to be captured in a rendering that is of perfect symmetry, but the reality of the situation has shown us that something is deemed more “beautiful” when it has some small “imperfection” ... I think this is likely something to do with neurological processing and how we are constantly looking to refine our weltanschauung (“world view”) and in doing so enjoy learning about new things and new angles, so “beauty” is something of how we cope and present how we learn, what we learn, and what we potentially may be able to learn - beauty, in this sense represents how we “enrich” our life experience and refine our understanding.
What may have caught attention hre is the term “refine,” which we can conveniently cut up and look at more closely in order to explore further. The route word “fine” has different meanings, one being used in phraseology like “fine-grained” and the other being the more colloquial “it’s a fine day”. The prefix “re” boils down to “again” so when we’re “refining” we’re making good again and/or looking at said item with greater precision or from different/new perspectives.
To come back to the question in the OP after looking into the meaning of “beauty” beyond it’s generic day-to-day usage. I think it is fair to say that art appropriates itself toward this schemata of “beauty” I’ve lain out. As an example to move toward some clarity of distinction we don’t generally refer to violence as “beautiful” yet if you happened to have watched any fight scene (I am thinking specifically about 100 here and the rendering of the comic book into a movie) many would agree that even though something chilling is being displayed with gore and blood the cinematography and choreography of that particular scene are “beautifully” rendered. What is it that makes this scene so instilled in my mind? There are a number of things, the least not being the interplay between the horrific and ugly facts of mortality and humanities evils juxaposition willing and heroic sacrifice toward some greater good - all framed in blood, sweat and tears and the tragic death of the “nobel warrior.” This is something that may be lost on a more youthful audience they just think it is “cool” never really digging deep to see what the scene means in the greater context of the historical narrative of humanity.
I think there is too much to say here in reference to Arostotle’s “Poetics” which I’ve taken a very close look at. One term that pagied me is “catharsis” and what Aristotle ment by this. It is something many scholars have argued over for some time. Obviously we use the term in a specific way today, but like many inherited concepts they often flip-flop semantically over time (eg. “bad” now often used to mean “good,” in phrases like “It’s badass!”)
Again to the OP in light of the above paragraph. Does art have to be beautiful? No. Does art have to be either beautiful or ugly or somewhre between? Of course. What is more, if some idea of absolutist “beauty” or “ugliness” is held up as a valid pole then that pole is a falsehood. If a work of art creates no controvesy and moves no one emotoinally I strongly argue that it is not admired by anyone other than the artist who claims it as their art (which is valid only for them at that particular time.)
Most of the argumentation is about competence. We can all sing along to our favourite song, but not everyone would be willing to call what we’re doing as “singing” (if you heard my attempts you’d not call me a “singer” ) Underlying the concept of beauty there are certainly some measureable patterns, yet given the variety of different human experiences and potentials we’re not in a position to distinguish between all works of art as being “more” or “less” beautiful, meaningful and/or masterpieces.
When you said previously that some people view a piece of art as “great” but not “emotional” I can only assume you meant a particular contextual use of either “great” or “emotional”. Generally myself and, I strongly believe (?), most people refer to something as “great” because they’ve been effected by it emotionally, becasue it strikes a chord in them, becasue they feel a degree of harmonious communion with the said piece. They don’t call something “great” if they feel nothing, although they may recognise the technical abilty in the production of the piece yet don’t find that it touches them (which I am assuming you meant?)
An example of this would be Mona Lisa, which I personally didn’t much like, yet I certainly appreciate the emotion conveyed, the quality of the rendition, and I am by no means going to say Leonardo wasn’t an artistic genius, but Monet’s Water Lillies entranced me, as do Degas’s paintings of ballerinas.
To the question embedded within the question ... What is Art? We could talk and talk and talk about that for a very, VERY long time indeed! It is such a widely used term that it makes subtle semnatic shifts from sentence to sentence. Again, looking back into the etymology does help a little and when we go right back to ancient Greece we see how the terms “artistry”, “science”, and “technique” become somewhat intertwined. We’re left with the difficult task of reintegrating them AND further splitting them into finer and finer threads in order to keep ourselves open to greater learning.