Walter Heller famously said that an economist is someone who sees something in practice and wonders if it would work in theory. Economic theory says banks exist because they channel loanable funds more efficiently than individual savers and investors pairing up bilaterally. Those informational, diversification and maturity transformation considerations imply that banks should be able to out-compete peer to peer (P2P) lenders. The stylised fact that few P2P platforms have made a profit to date is in line with this theory. If so, then P2P lenders face a difficult future and they may need to become more like traditional banks in order to survive. Either way, that makes them much less disruptive than they first appear.