You just use a pen to bring your algorithms or designs on paper. And optional you print out code you are currently working on.
That works when working alone, but also with many people. Because of course in the end - you use the computer to actually type your code in.
It's a good reader for individual docs and articles. The gesture recognition isn't perfect, but it's not bad. The software is getting better regularly. I tried installing an ereader (koreader? I forget the name) but it needed gestures that were tricky to pull off (for a task switcher).
Is most powerful feature is it's presence. It's just relaxing to look at instead of a screen.
If you're thinking of one, get it for what it's advertised for. If you want an epaper general purpose tablet, get a boox. I went with remarkable because (a) I liked the use case, I've had Android tablets in the past and they suck; and (b) it's open enough that it'll stay usable even if the company stopped caring.
For single person things though I definitely understand and respect the utility.
For me, the idea of being offline is just a way to:
1. Get away with distractions
2. make side projects enjoyable and avoid burnout because it doesn't feel like another job
3. make steady progress because of 2
Because the major problem for side projects or solo developers is not productivity, it's they either get distracted or burn out then abandon projects.
People who work in teams mostly have fewer of these issues because they are usually being accounted. Plus modern technologies did drastically improved how organizations exchange information, as opposed to pure productivity gain (just try to compare modern organizations with Office-like software and Internet connections, to paper-based government systems a century ago). So you probably need technologies to efficiently exchange information in teams, but not so much as an individual.