Actually, we use supported country list provided by brand. Just checked that brand and they are reporting for all listed countries, that's why listed as worldwide. We are considering to add "review" feature after purchase, maybe that way we can have user reviews that provide genuine user experience.
There is no detailed list on their site, only a warning that the use of the cards is prohibited in countries that are on the FATF list. Another provider of the same card had several EU countries on the banned list at the time, so I advise everyone to contact their customer support before buying the card and ask for confirmation that the card can be activated/used where they want.