I have never heard that something like that would exist in Europe.

Personally it's somewhat unlikely that I would have encountered it, because I pay in the currency of the seller whenever possible and let my bank do the conversion to EUR (their rates seem generally better what I have seen elsewhere).

Consumer organizations generally advise not to accept those conversions offered at the seller end. But the reason being the rate, I have never heard the reason to avoid an overseas billing fee. That sounds like an American/Australian/who else "invention".