I would image the majority of these types of payments will be of the the mico-type. If a single chain is to become the default, it will need to be able to handle these transactions.
402 Errors are returned by a website when you need to make a payment for access. Access could be a snail-mailed OAuth token, but crypto now makes this feasible.That's why I'm waiting.
402s been around for a long time, but "Reserved for future use": Already part of the HTTP protocol, and would just take BIP70 on top as a data format. BIP70 is new to me, will read up.
I don't dispute that. Personally I will use what works reliably and securely, whichever becomes commonplace is fine by me, so long as crypto is the underlying asset used for payments