I wonder about that. In theory it means you can have interest rates that are well below 0% (think of -2% or worse). The idea behind negative interest rates is that there is work to be done that cannot be financed at a 0% interest rate and that the interest rate has to be even lower.

If you assume 2% bank fees and a -3% interest rate it would be possible for banks to hand out -1% loans and that would allow financially insecure consumers to acquire loans because you cannot default by definition. Your principal will shrink even if you do nothing.

Will this work? I feel like it could work but it could also have unintended consequences.