Sure, but in person transactions don't scale well and if you act as an in-person money changer for large amounts of money you are likely to be criminally charge

Sure, but in person transactions don't scale well and if you act as an in-person money changer for large amounts of money you are likely to be criminally charged for unlicensed banking or money laundering. Most of the ones I've seen limit exchanges to less than a few hundred dollars to avoid bringing down the hammer on them. (It can technically still be illegal to exchange small amounts, but if the amounts are small authorities are less likely to bother.) They work for hobbyists messing around with crypto and people who want to buy small amounts of droogs on black/grey markets, but aren't going to allow crypto to be mass adopted. P2P marketplaces can record an exchange, sure, but how do you actually send or receive large volumes of Euros, Pounds Sterling, or Dollars without casting a "summon police" spell?