Of course you can use SWIFT, at the cost of bank fees, opaque exchange rates and waiting a week. You could also take a briefcase full of cash on a plane.
Whereas with crypto, you get transparent fees/rates, transaction confirmation in minutes, at any time of day, with a permanent cryptographic record of payment, and you don't unnecessarily leak information to the recipient's local tax authorities.
Transparent?! You've no idea what price the recipient will get for crypto sent.
I can hold foreign currency in my bank account (many banks allow this), so sending money in exact amounts internationally is trivial. And £20 isn't opaque or expensive. Much easier than putting a coin order in and then sending that.
Bypassing local law enforcement isn't a feature for me. These systems exist for reasons.
