It would be cool but I think that depends on the regulation of each country. One of the challenges of cryptocurrency as a form of payment is legality and the government.
Essentially, if it's accepted as means of payment, then it's a payment instrument. Some countries only recognizes cryptocurrency as form of investment and not a legal tender. It could be an issue if you run a mid sized business accepting a cryptocurrency in a country that doesn't recognize it.
I personally wouldn't oppose that. I have used it for so many things in the past, even there was a burger paid with steem/sbd. So, this concept isn't something new but again, regulation remains a challenge.
That is on point actually! Even my country isn't accepting crypto as legal tender so far. But the rules are about to be changed as we got to know the subject of crypto is been discussed in parliament. we are awaiting the final verdict.
Anyways, The subject was a part of competition which I found really interesting that is why I wrote about it. May be in near future I can literally propose this to some business owner.