[themihai]

Nothing really stops you from processing crypto-coins unlike credit cards where Visa and MasterCard have the last say. With crypto you no longer need approval from the platform owner. If you don't like Coinbase you can create your own coinbase-like platform. You have to remember that with fiat you don't have much control over your money either unless it's cash so I believe crypto-coins are a big step forward.

Buying fiat with crypto is another issue but as long as crypto coins are accepted widely there will always be ways to buy goods, services and even fiat.

[wastedhours]

Are there any checkout systems pre-built solely for holding crypto afterwards, and not for converting to fiat? Guessing Coinbase has to have it like that because they interact with wider networks.

If you wanted to sell a saucy story, how'd it work? Essentially a hot wallet with a webhook?

[wampwamp]

You’d just need an extended public key that gives unique addresses to buyers and a price API to provide rate conversions. Your private key can be offline or on a hard wallet. Also see btcpayserver for an open source bitpay clone that does what you are thinking and more