I remember reading some articles about the difficulty to have a fingerprint sensor under a screen, it might well have been easier to have FaceID (easier does not mean easy)
> Apple made this decision well over a year ago. Perhaps the fundamental goal of iPhone X was to get as close as they could to an edge-to-edge display. No chin whatsoever. There were, of course, early attempts to embed a Touch ID sensor under the display as a Plan B. But Apple became convinced that Face ID was the way to go over a year ago. I heard this yesterday from multiple people at Apple, including engineers who’ve been working on the iPhone X project for a very long time. They stopped pursuing Touch ID under the display not because they couldn’t do it, but because they decided they didn’t need it. I do believe it’s true that they never got Touch ID working, but that’s because they abandoned it in favor of Face ID early.
> I don’t know why recent supply chain rumors suggest Apple was scrambling to get Touch ID working on iPhone X as late as this summer, and no one at Apple seems to know either. Disinformation campaign from competitors?
Fingerprint reader on the back is unobtrusive and quite an intuitive way to unlock a phone. I can hardly find any issue or "major compromise" with it.
A physical keyboard on the other hand makes a phone at least twice as thick, twice as heavy, and twice as ugly (although the last one is more subjective).
If I had a dollar for every time I watched someone turn their Android phone around to look for the fingerprint sensor on the back, I would have a lot more free time to post on HN.
I highly doubt it’s easier to add FaceID than TouchID to any phone.