No, I am not referring my own mental outlook, but rather Plato's opinion as to why art is a waste of time and energy. Plato did not have a very high view of art generally speaking (e.g. poets and actors were to be banned from the Republic on moral grounds). But he did have a broad theory on beauty and art, and the arts did have a place - albeit a very limited one (mainly educational) - in society. To Plato, art is essentially imitative. When we paint trees, or people, we are painting a copy of a copy (hence the "two removes from truth"). If one is interested in seeking and knowing the truth, then why spend time copying copies of forms? Truth is to be known in forms. Interesting theory, but whether or not it is a waste of time to devote one's life to making copies of copies is a matter of opinion!
Aristotle's more positive view of art is right up my alley. As in most ways, Aristotle tempers and tweaks his teacher's theories. Not believing in transcendental concepts, and not seeing imitation as a bad thing, he sees art as translating into visual/written terms the universal elements in things. Imitation is natural to man, and he delights in "imitating". (Don't we all?)