It's not about street art, it's about a guy who is trying to make a documentary about Banksy. Definitely worth seeing though, it will really make you think.
Right, I didn't want to add any spoilers. It's still not really clear to me whether it's actually a hoax or not. If it is then there's no clear moral, and either way it's realistic enough that it doesn't really matter.
I think that there was a certain kind of moral; I think that he was making a statement about how absurd people's valuation of art is. That it doesn't even have to be about whether it is good, or original, or even who created it; a nobody could come out, make some shoddy knockoff artwork, and with enough promotion and buzz, create a market for his artwork and start selling it.
I think it's a reaction to the people buying and selling Banksy's own art; art that he created for free, in public, on the street, possibly on someone else's property or on public property, with no expectation of remuneration. Then, once it gets trendy and popular, people start buying it up just because other people are interested in it; they don't even necessarily care about the art itself, nor the artist, they just care that it's popular. By creating an artist out of thin air, peddling derivative, repetitive art with no particular meaning, and then ensuring that the hype increases the value of his art, Banksy is showing how disconnected the art market is from the art itself.
