The problem with this tool is you can't review your extracts at the same time you are reviewing your flashcards.

For example, if you have a list of 50 PDFs and you want to incrementally read them, Polarized doesn't have a way of scheduling when you're going to read all 50 PDFs. Supermemo, you don't have worry about that. IMO, that's the key feature of Incremental Reading.

I can chuck dozens of articles at a time into Supermemo, and do not have to worry about forgetting to read them. They'll show up in my reviews over time.

I'm wary that it might not be better than the tool developed by the guy who invented incremental reading.

I'd love to have something for it on mobile, because that's where I spend all my reading time, and that was one of the main advantages of Anki.