Maybe not for s20, but my note 10+ definitely notice the difference. Less error too.Testing on S20 Ultra and this seems pure placebo. Toggling it off and testing and then back on and testing and like that a few times I do not see any difference in speed to unlock. Biggest difference for me has always been just how dry (or not) is your finger. If your skin is really dry, expect a lot of misses or delays. I'm using the Snapdragon variant of the phone.
Edit: Definitely placebo. Did a blind test, where I didn't know whether the app was optimised or not and tested the sensor and many times when it was off I thought it was on and vice versa. This makes no difference.