I notice in the comparison the author has the cost of scanning the digital pages.

If you have an issue with organization, OCR, and interface, it seems these issues would be 10x worse if you’re digitizing your hand written notes.

Just the process of digitizing them with a camera is cumbersome. The quality of the image isn’t really great. Tearing up your notebook and feeding it into a scanner is worse.

So the author compares the cost of the writing on a notebook and phone to the remarkable but not the convenience.

Phone cameras have gotten good enough to reliably capture notes, and there’s software that’ll give you better results and are tailored to scanning documents. It’s a pain to have to scan everything by hand, but I find pen & paper to be an overall better experience, plus you get a built-in physical backup.

Is there any state-of-the-art OCR system on linux, which works reliably without too much fiddling?

I've had pretty good outcomes with Tesseract, but it's command line only and it's not even a small fraction as simple and straightforward and plain useful as the built in tools on Mac OS X.

https://github.com/tesseract-ocr/tesseract