Bank cards issued outside Russia cannot be used in Russia. https://payinrussia.com/ After you cross the Russian border, the convenience you are used to becomes inaccessible: you are unable to conveniently purchase a cup of coffee, book a taxi, or buy a museum ticket. You need to find a currency exchange office, keep cash on hand, and avoid unplanned spending.
A convenient solution is PayInRussia. This payment service allows visitors from other countries to pay for goods and services in Russia with their mobile phones. You do not have to carry cash or visit a bank branch.