You can't get (much) cash without the transaction being traced or criminal in many countries. There's a limit to legal cash transactions.

Arguments about amount are immaterial to me. Cash transactions of say $500k are physically doable in many systems.

And cash transaction don't require burning the Amazon, of course.

Then why should we use bitcoin?

Cash is a bit bulky and can't be sent over fiber.

Hawala is such a simple, effective, and relatively anonymous system that bypasses banking that the government had to convince the populace that anyone who uses it is a terrorist. It also helps they use the arab name even though it is of Indian origin.

As long as you're quick to cash in and cash out of it. Potential gains are fun, but losing 10% a month isn't.

That's not a real problem though, stablecoins exist.

You're not wrong, but the conversation was about Bitcoin, not cryptocurrency in general.