I am an artist as well as a collector of art and other things aesthetic.
Beauty is in the eye of the beholder, but it is often that many people can agree on certain art as being beautiful. The subject matter is not as important as the work of art itself, the composition, whether or not it is a successful work of art.
I often buy certain art because "it works", regardless of the subject.
Other times I am drawn to art by the subject matter and yet the art must have more to hold my interest, to fascinate me, and to render me helpless not to want it for my own.