Courts look favorably upon people who all along were taking steps to be within the law. So even if the speculation in it was wrong, it would likely have a big impact on any legal outcome.

I don't think nostr can be successfully construed as a money transfer system. I won't code for this thing and then hopefully I'll be just as liable as the company that made the disk drive that hosted the piece of data but had zero intention of facilitating money transfer... that is, not liable.