I think the Sony Xperia phones was one of the big proponents of this, where the fingerprint scanner is on the side, integrated into the power button. I never had an Xperia phone but I always thought this was a good idea compared to having it on the back or having it where the home button would be, since when you pick up the phone, your finger should naturally rest on the power button (assuming it’s thoughtfully laid out), and you can also use it when the phone is lying flat on a table, which you can’t do with it on the back.
I know some people are worried about privacy since then you need to use the fingerprint scanner if you want to use the phone, but those people will probably want to buy a non-Android Linux phone like the PinePhone or Librem anyway, and if those get a fingerprint scanner in the future, it will probably have a physical switch that disconnects it electrically, like they do for the cameras.
Personally, I like them over the more common back of the phone location or even the newer under-screen ones, and never under understood why they didn’t take off, but what do you think?
I had an idea for this but I’m not sure if any phone manufacturers use it. Place your finger on the scanner to authenticate, and then click the button to unlock. For turning off, I feel that simply pressing and holding should bring up the shutdown menu instead of unlocking.
Lg V10, V20 is like that and G6 was also like that. My V50 it’s just for unlocking the rear fingerprint sensor. The power it’s a seperate button. Press and old it’s ok, but the software was to be spot on because on my work phone the V20, press and old nothing, press and hold unlock, press and old again and it goes to the restart, shutdown menu… It’s a pain sometimes.