This sort of rhetoric is suboptimal. It only seems persuasive because you consider cryptocurrency to be analogous in purpose to cash, but the person you're trying to convince likely does not believe this. If they did, then they likely would already see purposes of cryptocurrency other than avoiding regulation, via the analogy.
If you're going to argue through analogy, you ideally need to ensure agreement with the analogy. Since asynchronous discussions make this difficult, we often need to settle for motivating the analogy instead. Simply assuming it is usually not persuasive.
Thanks for the advice. I use synchronous media like chat protocols much more often, and was blind to this- and yep, it does seem like the primary objection to that argument was born out of a flawed understanding of the analogy.
If you're going to argue through analogy, you ideally need to ensure agreement with the analogy. Since asynchronous discussions make this difficult, we often need to settle for motivating the analogy instead. Simply assuming it is usually not persuasive.