Here's one cryptocurrency PoC on micropayments: https://web3torrent.statechannels.org/ https://web3torrent.statechannels.org/ More directly to your point, I th

Here's one cryptocurrency PoC on micropayments: https://web3torrent.statechannels.org/ https://web3torrent.statechannels.org/ More directly to your point, I think lots of people have made attempts at micropayment protocols. The difficulty is psychological rather than technical - the cumulative mental burden of repeatedly deciding whether to part with a tenth of a cent "costs" much more than value being exchanged.