You can transfer cash in person by handing someone coins or notes. It might be illegal in some jurisdictions to do that for high amounts or certain items, but it is at least physically possible i.e. permissionless.
Bitcoin is that, but online.
The regulations you are describing affect what are essentially financial institutions operating on top of the system.
The act of sending Bitcoin is permissionless by design.
That's it, that's all it is. Nothing more, nothing less.
I’m sure there’s a niche somewhere. But when you say “pretty popular payment option”, it sounds like it’s a rival to Visa and Mastercard, and that prices would be listed in crypto instead of euro. That’s absolutely not true.
Re: Nigeria, anecdotally my few friends from the country tell me that the crypto boom is primarily about local influencers promoting their own coins as investments, not actual payments.