Given that interest-bearing loans eventually convert to ISAs if they aren't paid (through wage garnishment), it seems hard to argue that they aren't strictly worse for the borrower.
ISAs are not wage garnishment though. My ISA would be tied solely to the amount you're making and a non-interest-bearing predetermined price. Wage garnishment is a form of interest sharing, sure, but the underlying liability is growing at an exponential rate, which is what would be wrong.