At which point your local grocery store or gas station wouldn’t be accepting whatever currency is your current local currency. The point would remain the same - a currency doesn’t have to be universally accepted everywhere on the entire planet for it to still be a useful currency.
Does your grocery store or gas station accept Qatari riyals?
If that were my local currency, then I’m sure they would
At which point your local grocery store or gas station wouldn’t be accepting whatever currency is your current local currency. The point would remain the same - a currency doesn’t have to be universally accepted everywhere on the entire planet for it to still be a useful currency.