A few months ago I received a $50 Marriott Gift Card by email from Marriott. (It was one of the Bonvoy Elite loyalty thank-you emails back in May.) It's not a physical card, just an email from Marriott with the card number and PIN.
I checked the Terms and it says the card may be redeemed at "any participating Marriott brand hotel globally."
The gift card was issued in USD. Has anyone been able to redeem the card outside the US, in another currency (eg. euros or pounds sterling)? I understand there would be a conversion from USD to the local currency (although probably at a less than favorable rate). I'm going to Germany & France next week, hence my interest in the matter.