It's much more productive talking to anarchists.
You can refer them back to Kropotkin, whose issue with money was the fact it relied on a central issuer which in turn gives rise to a state.
Many anarchists have adopted this view so fully, they tend to dismiss all discussion of money and carry the axiom "we must therefore find ways to have society without money".
So they're easier to win round as you bring them back to their own first principles -- the lightbulb goes on as they see that bitcoin is a form of money the great anarchist thinkers weren't able to conceive of and therefore a world they want is more possible than before.