This is good because it solves a problem for small borrowers/lenders in a nice way, just like micro lending does, but this would not work for larger amounts. Over the last 10 years, inflation in the US has ranged from 1.5%-4%. So if you are putting a large amount into a zero interest (or, low interest) Savings account, you are basically losing money.

Unrelated side note: If you have any more than 3-months expenses in your Savings account, take them out and put them in a NASDAQ or S&P index fund with low fund expenses.