Well, I haven't seen any banking (borrowing and lending) systems built on top of a cryptocurrency yet, But that is probably largely because there isn't a good

Well, I haven't seen any banking (borrowing and lending) systems built on top of a cryptocurrency yet, But that is probably largely because there isn't a good enough reputation system or other way to encourage the payment of debts that is compatible with the cryptocurrency ecosystem yet, I think. Or, alternatively, they exist and are used, but I haven't noticed them yet.