Oh wow. I never seen USD accepted in Thailand

It's not common at all. My experience is that any crypto or Bitcoin is the same practically: virtually no one wants to take them, so you can cash out from a local exchange to local currency. People do generally want and understand dollars as the best currency. That's an easier sell than Bitcoin for now. I did use lightning twice in Vietnam. There's an app called Neutron pay that connects Vietnamese banks to a lightning wallet. My Vietnamese brother-in-law asks for USDT any time I want to send him Bitcoin.

Usdt in El Salvador? I’d love to investigate! Yah I’ve seen it a bit but it’s way less prevalent than btc.

That's great to hear. I was bummed to hear my friend's experience. He did spend a lot of time in smaller towns, so maybe that's the difference