Because it's the new Touch Bar! We've taught people for decades that dynamic user interfaces on this level are a bad idea. There are studies showing that dynamic user interfaces on this level are a bad idea. Microsoft Office is using dynamic UI and it's a terrible experience. Apple introduced dynamic user interfaces with the Touch Bar only to drop it a few years later. They didn't learn their lessen and now we have this. Don't get me wrong, it looks cool, it draws attention it's new so naturally people, especially Apple fanboys, are all over it. But it introduces more problems than it's fixing. The Touch Bar was useful in some cases, this seems more like a gimmick.
I just discussed it with my friend and a long time Apple pro user. We have exactly the same thoughts. I wouldn't be surprised that in 2-3 years Apple kills it like they did with touch bar, like they did with 3D Touch.
What is genuinely surprising to me is how tapping with your fingers into the selfie camera and FACE ID sensors is considered a good experience? Usually Apple is a lot more thoughtful about these fundamentals things.
At the very least, its nice to see their crack marketing team living up to its name with an outrageous slogan