I think that reflowing text is perfectly fine for reading fiction which lacks graphs and meaningful formatting beyond section titles. For non fiction I find re

I think that reflowing text is perfectly fine for reading fiction which lacks graphs and meaningful formatting beyond section titles. For non fiction I find reflowed epubs sometimes inferior to a pdf perhaps to a degree more aesthetically than in terms of actual usability which is harder to quantify. Below a certain size this has exactly the defects you describe however I find that on a fairly large wide screen in landscape orientation it is quite readable. For example a screen 6in wide lend themselves well to reading without zooming. This is largish for phones or smallish for tablets. Regarding dictating layout and aesthetics for practical purposes most of your users aren't actually dictating much of anything beyond screen size, platform, and zoom level. Just because other settings exist doesn't mean most people use them. For practical purposes there are small screens where text must be heavily reflowed because not much fits on the screen and screens big enough to show a whole document depending on font size. For most things you want to support the first use case if any portion of your users are going to be on phones which is nearly always true. This doesn't mean that there isn't a case for designing a non mobile version of content especially if its mostly consumed outside a limited and limiting screen or benefits from such.