The bank has a legal obligation to fulfill those IOUs, which in practical terms is essentially as good as "owning" the dollars. There is always the risk of a B

The bank has a legal obligation to fulfill those IOUs, which in practical terms is essentially as good as "owning" the dollars. There is always the risk of a Bernie Sanders kind of scam, but it's rare enough and regulation is heavy enough that for the common person it's not a real concern, or worth worrying about. Coinbase is regulated similarly, though obviously they are young and have to continue to prove themselves over the course of decades.