the unit economics of micro-txns simply don't work with traditional payment rails...they can either adapt/adopt blockchains for settlement (like @Visa is doing) or go the way of the dinosaur! blockchains aren't perfect yet for risk/auth scoring, but things like ERC-8004, @zauthx402, and @CoinbaseDev's CS2 (private risk eval api) are all making good progress on that front already