I had two Samsung flagship phones, one (S20FE) had an optical fingerprint reader and the other (S22) had an ultrasonic one. Both of them somewhat regularly failed to read my finger, were slower than a fingerprint reader on the power button and are more expensive/complex to build. They won’t work with cheap 3rd party screen replacements and some screen protectors as well.
Meanwhile my $90 Android phone has a fingerprint reader on the power button. It never fails and I never have to perfectly place my finger on the sensor area to get it to work. It just seems like the perfect place to put a fingerprint sensor, so why do phone manufacturers keep using in-display fingerprint readers over the cheaper alternative?
It became a big thing on android just before covid happened. Unfortunately, masks completely confused it.
I currently have both active on my phone, it’s about 50/50 which unlocks it first. I tend to unlock my phone as I bring it out of my pocket via fingerprint. If that fails, then face ID kicks in.
Apple quickly implemented a Mask FaceID scan so you could unlock with mask, I used that or just swiped my watch for payments etc. I did see quite a few android friends go back to fingerprint I remember
It took them a few years, if I remember right, though they did add the unlock-with-watch pretty early.