FaceID is much slower than TouchID, FaceID fails with wet glasses, it fails with a breathing mask. I can’t use the phone with wet fingers or gloves so needing a bare dry finger for TouchID is fine. FaceID annoyingly worse.
All you typically need to do is lift your head up so FaceID can get a clear look... but when I'm sleepy, it's annoying.
Ideally, the phone would just have both... somehow... but this seems technically infeasible so I get it