Why Make Art?
Banksy’s role is to make people aware of what’s hidden in daily modern life, as with many other artists. A good example: the truck with stuffed animals, driving through Hell’s kitchen.
To further art aesthetics
To add something beautiful in the world
To add something empirically educational
To add something educational for humanities. If one believes in absolute truths, this is okay. Narrative (film, books) can be destructive a la propaganda.
To make people aware of the bad things in society. Sounds like the reverse of the above.
Because one has leisure time, and one is passionate
To express a thought in a form that a mass amount of people can consume it at any time
to make a beautiful educational experience