Why not if they can earn some commission.Goldman plans to clear bitcoin futures for «some» clients. What «some» I imagine is for those with plenty of margin in their accounts. As Adam pointed out, the futures exchange will require 35% margin. The clearing brokers like Goldman might demand more margin.
My version of Bitcoin is trading at $16,410 currently, just off my high at $16,777.08. Some exchanges traded as high as $19,000 in trading today — which is scary.