It doesn't HINDER functionality, as it's not taking the functionality away. This is no different than someone getting used to TouchID to unlock their phone instead of putting in a passcode. The functionality simply is adapted to given the device that they're using in particular. The overall functionality is still there, regardless of how you obtain said functionality.
The only argument you could make as far as taking "Away" or hindering functionality (in my opinion) is the removal of TouchID, in which case I could unlock my phone without having to direct the phone to my face. It was easy to do while passing on a counter. Can't really do that with FaceID. But the notch does not take away functionality.
The new gestures that you're referring to have to do with the removal of that exact button that did house TouchID, and not with the notch.
So technology, or anything for that matter, should never evolve?
- Apple should have stuck with a 30 pin instead of lightning
- Micro-USB should never have been replaced with USB-C
- Analog TV signals should never have been replaced with Digital
- Why bother with 4k when 720p was perfectly fine
- Bluetooth? Why go wireless when we could easily plug things in
It's never "necessary" to change something until something more efficient can come along. Something to make the experience better, or change it for the better. In this case, we get rid of the huge chin and forehead on these phones which have been rather ugly for years. We also get new gestures (which you claim to see now need for). Will it take a bit to get used to taking screenshots differently? Sure. Will it take a little while to get used to having to swipe up for home? Sure. But with your logic, we should have never moved away from buttons on a phone for a keyboard, we should have never given up the number pad from flip phones. Why change the functionality? Was it necessary?
I will say that if there is one gesture I'm truly EXCITED For, it's the swipe left or right to switch between apps. Omg that will make my life a ton easier when navigating my device as my job demands that I use several apps on my phone, all day, every day. And the majority of the time I will switch between 2-3 of those apps. Double pressing the home button and finding it on the app switcher is kind of a pain in the rear. If you've not seen a video of this in action, go look it up. It's slick as hell.
I get you're frustrated with the change, but that doesn't mean that change shouldn't happen. It's, again, just something to get used to. At the end of the day, after a year or so of using it, you'll most likely be very used to it and it will be an afterthought (Assuming you're purchasing a 10). That being said. Gestures aren't going to go away. Home button isn't going to magically make it's way back. The notch, however, may disappear, which I'd assume will be much to your pleasure.