If cigarettes became a more attractive medium of exchange, is it illegal to use that medium between two private, consenting parties?
https://en.wikipedia.org/wiki/Legal_tender
It doesn't prevent you from accepting other means of exchange (though in some countries it does), but it does force you to accept it, even if you don't like it.
Tim DeChristopher spent 21 months in prison despite how he "had raised sufficient funds for an initial payment to the BLM (which the BLM refused to accept)."
https://en.wikipedia.org/wiki/Tim_DeChristopher#Trial
(I bring this up because I'd always wondered about how why that case fell out that way, and apparently it can't, per the common meaning of the terms, so my understanding of legal tender seems correct?)
Last year, I tried a bitcoin payment card. It was not practical because of bitcoin volatility, but there was something super cool about it : it was a prepaid rechargeable card that I could recharge in the hour, by sending bitcoins to it. I always knew how much I could use on the card and could basically use everything that was on it, without fearing to hit some obscure limit.
This was the perfect payment method for me. I hope we'll have something similar to this but with non volatile currency soon (I know this exists for fiat, but I have to wait like 2 days for a wire transfer to happen, this is not practical).