Mutual mircopayment channels chains(net) would give Visa's throughput:

Alice <==> Bank/ProxyServiceA [<==> Bank/ProxyServiceB, ...] <==> Bob

or

Customer ---> Bank/ProxyServiceA [<==> Bank/ProxyServiceB, ...] ---> Merchant

where
<==>: long term(monthly, yearly?) mutual micropayment channel
--->: long term one way micropayment channel


requires malleability fix