On the other hand, the closest equivalent in the rest of the Nordics (Denmark/Norway/Finland) is Vipps/MobilePay, and you must have a Visa or Mastercard card to use it.
You must have a debit card, but most of these cards are BankAxept cards that happens to be dual-branded with Visa or Mastercard. At least in Norway Vipps payments go over the BankAxept network (Vipps owns BankAxept which handles 80%+ of Norwegian in-store payments and an even higher proportion of Norwegian debit card payments), not over Visa or Mastercard.