It’s more than a hassle, it’s illegal and/or against the card network rules.
European law states the currency that customers are charged in must be agreed before the transaction, and if currency conversion is offered the customer must know all charges and the exchange rate beforehand too.
Mastercard and Visa, which facilitate the majority of consumer global payments, also say a customer must always give permission for a company to bill them in their own home currency rather than local currency. This means any business, wherever in the world you are paying, should not be overriding or changing your choice after you enter your PIN.
And this isn’t rubbish, it’s reported to be a problem.