There’s a hierarchy of reader-seriousness even within the e-ink faction.
A truly serious reader does not want any wasted space on pages – no titles, page numbers, paragraph breaks, margins, any white space at all.
Never mind progress bars or any indication of the length of the book, a worthwhile book is as long as it needs to be; it will end when it should end.
Book covers are another lamentable waste of space; only content matters.
Reading efficiency is important. The ereader should be held and operated with one hand with no unnecessary pauses to put down a coffee cup or a baby to free up a second hand to turn the page.
I do slightly prefer e-ink (although not knowing any better I spent many happy years reading on Pocket PC and phone screens) but I’m irredeemably frivolous. I just want to wallow in my Golden Age mysteries, attractively spaced on the page with the title at the top. In between books (or chapters even) I often pause to admire my book covers; I’d like them even better if they were in color.