But then what's the appeal of charging BTC for those services and goods if they could charge USD or EUR or other fiat currencies at a higher price? There isn't one.
Yes, there is.
When I charge all my goods and services with BTC, I have no limits on sending and receiving money worldwide, at no fees at all.
And I can be sure I will not be screwed by any financial institution or Paypal-like, with freezings and chargebacks shit.