Although Samsung Pay is undoubtedly one of the better payment portals out here, its wearable version leaves a lot to be desired. For starters, it is only available in a handful of regions and supported on even fewer devices. The functionality has expanded to users in Germany who will now be able to use their smartwatches to make payments via Samsung Pay. It supports the 'Splitpay' payment system too, allowing you to make purchases in installments.
An active Samsung Pay account is mandatory for the process, which needs to be created via a linked device. The Samsung Pay app is available for several other Android devices too, so you're not restricted to Galaxy-branded smartphones. Samsung has tied up with Solarisbank AG, making it easy for users to link any bank account with the service. Once your Samsung Pay is up and running, it needs to be activated on the linked smartwatch via the Galaxy Wearable app.
Samsung Pay can be used with the Samsung Galaxy Watch, Galaxy Watch Active, Galaxy Watch Active 2, and Galaxy Watch 3. To initiate a payment, one has to press and hold the 'back' button on the smartwatch. You'll be prompted to enter the PIN once. Subsequent payments will not require a PIN, but you'll need to reauthenticate every time you take the watch off your wrist. However, what constitutes 'taking your watch' off remains unclear. The feature will work only with NFC-enabled terminals, though. It's been a while before we've seen a Galaxy wearable with MST, and it isn't coming back anytime soon.
Source(s)
Samsung (in German)