He adopted it just because he believes in it and wants to support it.
You should have read my view... Not trying to suck up but I'm pretty sure he's allowed to do whatever he wants.
He can but a lot depends on what he does. He is a public character for Bitcoin and the entire community. Anything comes from him will have million times market affect than you and me or others. 
Anyway the advertisement worked and I paid for my copper membership. I hate to see the other payment method though.
