Can't speak to using it for payment, but I had a Samsung Galaxy Active watch in 2021 that I loved, but it was not well made at all.
The case of the watch wasn't a solid piece like it is on the Apple watch or the Garmin Venu (which I have now). The underside of the watch was glued on. Within three months it had separated from the body of the watch, exposing the innards and the heart rate sensor. I sent it off and Samsung repaired it (by gluing it back on) but less than a year later it came off again, not under warranty any more. I tried Gorilla gluing it back on, but it didn't last. I ditched the watch in disgust. I shouldn't have to do that for a watch I paid $200+ for. I'm much happier with the Garmin I have. It has Garmin Pay, but I haven't used it yet.
Maybe Samsung has redesigned their smart watches since my negative experience.
@phoffen to use the pay feature on a smart watch you have to put in a PIN, just like you do on a phone. After a certain amount of time (30 seconds or whatever) if you haven't made a payment the feature closes and you'd have to start over.