If you are in a country with a big inflation problem, like Turkey a few years ago, it was painful for them to quote an hotel stay in, let me say, 5 months time in their local currency, so they quoted the room rate in USD and quite often the final bill was charged in USD. Do not worry, since the drop of USD vs EUR, now they are quoting their rooms in EUR.

Similar thing in Egypt for diving centers, their staff is mainly foreign and paid in USD, plus they purchase abroad the equipment so it seems only normal to them to charge their customers in USD.

In London, a lot of shops are asking if you wish to pay in EUR. With Visa and Mastercard is an option but if you use an AMEX it was not possible, at least to me.