The main advantage for me of a dedicated e-reader is that I don't get distracted and do something else, which happens to me constantly when I try to read on my phone.
Put it in airplane mode?
Oh, sweet child.
Airplane mode can be disabled as quickly as it was enabled. As can Raycast's 'focus mode', which is why I'm typing this (on my laptop) and not reading my book, and why a thread about cheap e-readers immediately caught my attention.