Or you can go to the bank and pay their exchange rate. Maybe they'll ask you for your ID too.
Another example of the second kind: www.Ape.tax, where anyone can deploy an investment strategy and beta users can try them out, and if they are successful, they can be integrated - voted on by a DAO - into Yearn.finance, the primary project with several billion $ in investment.
There are existing projects already using the situations I talked about. It's not theory. It's not idealized vision. It's happening right now.
Blockchain is moving so fast that Yearn.finance, the platform with billions in investment, wasn't even a thing a year ago.