What is good collateral for a loan?- Identification that is clear, verified and can be linked to you and trace you
ID is not acceptable collateral for a loan.
If it can be used to trace someone back to their house or such, then I would consider it acceptable. Proof of ID, not the actual physical ID

It's important we use the same definition, so I look to the dictionary which says collateral is security for a loan.
While identification helps prove a person is who he/she says, it does NOTHING in helping secure the funds.
You don't want to fool new users into thinking it's safe to lend to someone because they know who they are - its NOT.
Collateral is something to fall back on - something to sell - should the borrower not repay his debt. ID cannot help with that.
Re-defined in the OP.