I totally didn't understand "fiat has value because of taxes" when you first commented this. But then I heard this sociology professor tell the actual historical story of money and coins, and it all made sense! I had been believing the economist's story of money - that it developed because of a need for a common unit of exchange - which isn't actually historically accurate and leads to a real misunderstanding.
It reminded me of this convo and I had to come comment. I think it's a very important misconception to correct if you're going to talk about how fiat has value bc of taxes.