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.