Learning about yourself and what's around you is entertaining for some. Philosophy can be entertaining. Music is entertaining. The same can be said about any piece of art.
To me, there isn't a objective difference between a cartoon and a painting from 1455. The end result is entertainment regardless. The cultural and historical ties that painting has are real, but thinking about all that and interpreting that painting is still entertainment.
Since art as a concept doesn't really differentiate from being a form of entertaiment, art is stinky poopoo trash.