Well I guess that's a fair question. The human need and ability to create and appreciate art on an emotional level is one of the things that sets us apart from the animal kingdom. From a simple hand print in a cave to exquisite Egyptian artifacts we humans have been expressing ourselves from when we started walking the planet on two legs. Gibbons can walk on two legs too, I think, they are not renowned however for their apprecation of or ability to create art.
You'll be pleased to know therefore that buying original art proves to the rest of us that you have evolved sufficiently and are part of the Human species.
As I see it, without art or decoration, produced by artist's, your living space would be a pretty dull and uninspiring place to be. Imagine a room with bare walls, no decoration, no colour, texture, or pink fluffy cushions if that's your thing! of course if you are happy with the the prison cell look then you probably don't need any art whatsoever, or you're in prison!
If you are part of the human race, not locked up and you wish to enrich your environment, express your personality, show taste to your family and friends then you're going to need some art.
Art enhances the spaces we live in. A piece of art can be humourous, tranquil, challenging, decorative, stylish, emotionally meaningful and much more. Whatever reason you choose your art is always great means of self expression.
It's a perfect way to show the world that you have a individuality. It can be sophisticated and stylish or simple too, etiher way the choices you make are a great experience waiting to happen and if you get it right it could be the coolest thing you ever do, after all Steve McQueen collected art and he was known as "The King of Cool"!