You're just going to run into loads of people who don't understand what "legal tender" is and, when you explain it, will insist that you must be wrong because they've heard that phrase and attached a different meaning (generally: a vaguely positive aura plus "it's money")

For those reading along, a useful baseline to get you straight on legal tender is in countries where fiat currencies are just broadly assumed to be valuable any legal tender laws are basically just ornamentation. Scotland, for example, doesn't have any bank notes as legal tender, just some old coins. Nobody in Scotland doubts that the notes they have are valuable, but its laws don't bother explicitly privileging this as "legal tender". Nevertheless if you get on a bus in Edinburgh with a goose and some shiny rocks and try to barter, well, you'll be lucky if the other passengers let you back off in one piece, let alone to get an actual ride. "Exact cash fare only".