A printed book requires light as just about it's only dependency!
I definitely agree with you about the distractions of digital devices. Switching to a book is a focused mode.
Because I want minimal complexity. (Usually in the tropics, often with rum and a hammock)
Dead tree books' short term failure modes are water and fire, and once failure is confined to emergencies-that-are-already-emergencies they impose no additional cognitive burden.
Also, I suspect the physical friction involved in "swiping away from" paper books helps reset my dopamine baseline / memory, but that's just suspicion from having lived pre-smartphone.
PS: Also, re: environmental impact. eBay and Amazon sell tons of used books. Sure you're shipping them around, but I really buy new these days.
I don't consider an e-ink reader very complex. You charge it once in a while, download books to it once in a while, and otherwise it's basically a book except it remembers what page you were on.
I used to take my e-reader on field expeditions when I was an archaeologist. Never had one die or break even after months in places like Siberia. The number of notebooks that were ruined during those same expeditions is non-zero, usually from condensation or the physical trauma of a backpack.
This is why I find "saving space during travels" a very relative argument to make, because it's clearly down to preference.
And the "charger" I need with my ancient Kindle is a standard micro-USB cable, not exactly exotic. And as soon as this one breaks down, the next one will be USB-C like a good 90%+ of my devices I travel with.
I don't personally travel with a laptop unless I plan on working remote. Too heavy/bulky and more importantly, you need to take them out going through TSA. The e-reader doesn't need a charger for the 2-4 weeks I usually travel. If I'm traveling longer, I'll bring a single additional USB cable (that will go away the next time I upgrade).
A phone doesn't take bag space because it's always in my pocket, but it's significantly less ergonomic and much less power efficient for reading. The value-add of being able to read without draining battery on my most important travel tool is worth it on its own.
Light being a dependency of reading a printed book is one of the biggest plus for e-ink readers. You don't need light, they already come with it! It's so much easier reading with a Kindle (in dark mode) at bed time than it is a paper book.
I suppose the use case is picking up the kindle at night in a dark room while you disabled the light when you were reading outside during the day.