Please help me understand/explain to an economist friend of mine...

He argues that Bitcoins have no chance in global success because a this system be used to create credit.

Bitcoins cannot be used to leverage. --> You cannot use Bitcoins to create credit.  ---> It can't replace existing credit already created by the current system.

For Bitcoins to be successful, it has to be able to replace the existing debt!

Please help me:

Where is he right/wrong?