In his book Fighters Heart author Sam Sheridan goes to Brazil and trains at a top school and notes the prevelence of BJJ practitioners using MJ. I can't remember what team he was with, but I do remember him saying he was with a group including Murillo Bustamante. Anyway, he said that they BJJ culture and surf culture are very much entwined down there. Said alot of guys regularly smoke out.
Personally when I used to smoke it just made me think differently. It certainly helped with creativity. And I'd imagine that it could only give you another angle at which to think about your BJJ game, so I think it probably does help some develop.