The backside fingerprint reader could even be used as an input device on some models for scrolling, or pulling down/up the notification bar. Great for scrolling through content or swiping through screens without having to cover your display for gesture input: https://www.androidauthority.com/miss-rear-fingerprint-scann...
This is one of the big things I miss from my Pixel 5a; it was so nice to be able to unlock the phone and pull down the notifications bar with one hand. There's a lot I like about the Pixel 8 Pro I replaced it with, but that's one thing I miss.
There was a "healthy" phone called the Bloc Phone which had the screen in Black & White by default but allowed you to use the fingerprint on the back at any time to give you a few minutes of colour when (say) looking through your camera roll. Really cool idea.
Exactly--this plus the usability original commenter communicated made this why I did so much work to keep my Pixel 3 alive for so long. I still think about the rear fingerprint sensor after a Pixel 3 -> pixel 6 -> S21 Ultra -> S24 Ultra journey, and further how much fun i had back in the ROM + kernel + modding + undervolting days.
Ironically, some devices (Pixel 9 at least) have now added a tiny little touch sensor exactly where the fingerprint reader used to be - it doesn't read the fingerprint, but you can regain this functionality by mapping taps to actions.
I can't even imagine why they decided to keep the fingerprint sensor on the front but add a whole separate sensor on the back.
Are you talking about the feature "Quick Tap" in the settings where you can double tap the back? There's no sensor for that, they just use the accelerometer to detect that input. It's been incredibly unreliable for me.
Yeah! I use that quite a lot on my Pixel 4a. It's particularly useful to close the system quick settings, since I can just scroll once instead of 4 times x)