I’ve used an iPhone X and XS. Touches on the bottom part of the screen (which replaces the home button) don’t interfere with touches on the other parts of the screen (so you can keep your finger on there and still use the phone), however they aren’t ignored per-se and will still trigger some events like bringing up the controls on the media player or something.
Not a dealbreaker but honestly I still prefer true safe-zones where there’s no way the phone can feel anything on there.
This could be addressed with software. I assume that’s what’s going on in sci-fi adaptations of “smart slates”. They’re clearly a powerful platform, but it’s all for nothing without the right UI.
Honestly, unless software can read my mind to tell whether I intended the touch to be registered or not, I'd rather not have that.
No software solution is going to be 100% prefect and you'll end up with either degraded experiences (as an example, when you tap a link on iOS, there's a bit of latency - this is because it's waiting to see if it will be a double tap), or dangerous mistakes where it will still register touches that weren't intended.
As our phones contain more and more data and bear privileged access to a lot of systems (work, etc), an accidental touch can sometimes be disastrous. I have a friend for example that's a complete idiot with tech and never locks her phone despite holding it by the screen and pressing random stuff on it. Eventually she accidentally pressed the voice message button on WhatsApp and ended up sending a good 5 minutes of a very private conversation to a stranger.
Not a dealbreaker but honestly I still prefer true safe-zones where there’s no way the phone can feel anything on there.