I think a central non-technical question about peer-to-peer credit networks, regarding why people would or would not want to use them, is that combining money and friendship is often a recipe for trouble. Even with business relations, most people or economic actors will want to "anonymize" their credits asap, that is, they want their credits to be independent of any outside actors.
Of course, when your money is in the bank, then that *is* a credit relationship, and that bank is your neighbor in humanity's global credit network. But when a bank owes you money, it feels less relational than when a person, employer or shop owes it to you. Even if "the bitcoin bubble" owes you value, that may feel psychologically safer to some people than when your credit is stored in, say, Amazon Gift Vouchers.
After all, Amazon or any named agent owing you money, can always decide not to let you redeem your credit so your agency is limited by another actor. People therefore probably tend to prefer more "faceless" IOUs over more "relational" IOUs, and that might well be why even in trade credit networks, actors might want to "settle" (for any meaning of that word) their accounts.
People just psychologically/socially prefer to borrow from//to strangers rather than from/to their own relations.
Does this idea ring any bells to people?