A number of things are steps back. Scrollbars used to be easier to click, and would always tell you when you were somewhat far down a document. Now they disappear when you're not using them. Since we have SO MUCH more screen real estate these days, I don't even buy it as a practical measure. I believe this style is meant to reduce visual clutter from an aesthetic point of view, but not actually to improve the usage of the computer.
Agreed, it forces you to flail around the UI to make elements appear before you can use them. Combined with my MacBook's TouchBar that goes to sleep if you're thinking and not using the keyboard constantly whilst debugging, it drives me insane as you have to press a key to wake it up for no purpose, look down, find F6 or whatever for continue/step over because there's no physical keys and it's like pressing a ruler, and then flail around to get the scrollbars to appear.
It's such a regression in usability. Imagine if they did this in cars - simply wave your arms around for the steering wheel to appear when you need it!
