Well, for the bank it makes a difference since a backed loan (eg most things real estate or other collateral) are generally less risky. While things without collateral (e.g. student loans) are more risky.

In the EU the Basel laws limit how much a bank can lend out depending on risk and foreign capitals (e.g. deposits) and own capital (what the bank legally owns itself). So having lots of secure mortgages or having few risky loans which would both be according to the law actually do make a difference in the amount of money supply increase wile just being a different risk/return ratio for the bank.