A lot of what you're saying here resonates with me, I've touched on some of these points myself in this conversation. It definitely isn't great for anything that requires actual thought. Your comprehension does suffer as your reading speed increases. The whole industry surrounding this stuff really does oversell its capabilities, which is why I tend to set a practical limit rather than touting some massive number.

Where I think the argument starts to break down is by lumping all reading into a single category. Reading a novel for pleasure, and wading through forty pages of background information before you get to the five crucial ones, are fundamentally different activities. I'm a medical student, and the majority of my reading consists of that second type. You can't really "digest" a literature review in a way that makes it enjoyable. The only real goal is to get through it once, without getting bogged down.

Regarding the pauses, that's actually the area I put the most work into. It lingers three times longer at the end of sentences and twice as long at commas, specifically because a consistent, flat pace feels like reading a script rather than actual prose. And, of course, you can pause whenever you feel the need; there's no pressure to keep moving forward.

The part I'd really push back on is who this is actually for. The people who've given me the most in-depth feedback today are clearly avid readers. It's not really a tool for people who don't read much.