it might have to do with the fingerprint scanner being embedded in the screen? or are you sure your brightness is at 100% when you are trying to scan. I just don't see how that feature can be removed. It might just be a fluke that it didn't scan?
So, an interesting experiment: When I manually increase my brightness to max (even the non-boosted max), Samsung pay *decreases* the screen brightness automatically when I tap 'use card'. It increases brightness at my standard levels, but it actually decreases the brightness when I try to manually increase brightness! This has worked flawlessly on my last 3 phones, and this isn't a feature I want removed, so I really hope it's a big they just didn't notice, as opposed to hardware they stopped supporting.
(I just deleted a too-long post about my Samsung-exclusive smartphone history going back to my Omnia [pre-Android], and how Samsung often misses the boat, thinking we remain as fans because of their big features, when quite often, it's the features they don't tell anyone about that really keep us coming back for more. When it came to updating to the Note 10+, fancy s pen features weren't part of the decision. I just want s pen, not gimmicky s pen. And this ability to empty my wallet of all of my cards, yet still use them with ANY scanner turned out to be a big player in my decision not to wait for the Pixel 4XL.)