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. They may also impose other hurdles for clients.
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.
