Me asking myself "how long is this article" before I start reading it is a distraction? Too bad, I can't help but want to know. I could've learned that instantly by unconsciously glancing at the scroll indicator, but instead I have to move the whole content down for it to appear (possibly with a whizz-bang animation, no less), introducing friction and further distracting me from the content. Good job, I guess.

There are margins on the screen 95% of the time, it's a perfect place for a tiny 1-3px scroll indicator.

>Actually, yes, when was the last time you looked at a page number in an e-book? Every time I read an ebook, I look at the page numbers. I would be frustrated without knowing where I am or how much longer I have to go

Actually, they very much do:

1. As a relative marker of a current position.

2. As an absolute number when your ebook/reader screws up saving its state.

I'm convinced designers have since long overthrown human-machine interaction experts, and usability consistently went down in the search for what's visually appealing and cleaner. I particularly blame Apple as a trend-setter in this, along with everyone that dumbly followed the fashion. No appeal to authority will ever convince me that disappearing scroll indicators are good for me, as I've been burned by them and I see less able people around me having ever increasing difficulty navigating modern interfaces thanks to similar innovations.

The "professional experts" are not interested in usability. They care only about sales and/or engagement. You can see this in every consumer product, not just software.