It's looking like individual companies will have to run their own securities now.  Which is fine, since it's 1 less entity to trust.

If I were to loan someone bitcoins, I wouldn't do it unless the full loan balance was backed up with collateral provided by other people.  People could "vouch" for someone they know is trustworthy by offering some of their coins as insurance.  In this scenario, the "bank" would just be a gathering place for people to offer crowd-sourced loans.