I think maybe collection should be free.

If I loan you $10 and you don't repay it, it's never going to be worthwhile for engage the legal system to reclaim that money. If there's no realistic threat of coming after somebody for $10, then no $10 loans will be offered. I think it's nice to have an environment where legal remedies are accessible to everyone for little to no marginal cost. It promotes pro-social behavior if everyone knows that everyone knows that contracts are always enforced regardless of the economic standing of the participants.