I mostly read novels and I do most of my reading on a 5" phone, which I think is just the right size for me. It's always in my pocket. It's simple to hold in my hand. It's line width is just slightly wider than the text column in a newspaper. It's perfect. For me!
I do have a Paperwhite and I like it just fine. But I do nearly all of my reading on my phone. And to save it's battery I have a second phone about the same size but with no service that I keep synced. That way I don't use up my main phone's battery. But my main phone is always with me ready to read wherever I am.
I do think it's a mistake to say that nothing else makes sense. I didn't start reading on my phone till a year or two ago and before that I was perfectly happy reading on my Paperwhite.
A reading device should be something we're comfortable with, not necessarily something that makes sense. That makes sense to me.
Barry