Simply because of the nature of perception. The difference between the two is also mostly subjective unless you reduce it to a matter of technique. But fundamentally whether it's good or it's bad art, it's still art, because it is intended to be art.
I picked Being creative and innov something. Yes, art can be anything in this world, but if your original or a fan of something, be creative with your piece and that's art. Just drawing something in like 3-5 minutes isn't what I consider to be art, unless they're like experts at it. I just feel, that if you really love art, and is really emotional and have your complete emotions in it, come on it needs time. Shouldn't you try to make it look exactly like you want it or feel it to be?