I care for hyphenation (in german there are more lengthy words than in english). That is one of the reasons I use a kobo. And yes, hyphenation is the "correct" way of typesetting justified text. BUT first there are many people who just doesn't care. For them it is totally unimportant if a reader can hyphenate or not. Then there are the few who don't like hyphenation at all. And then there is the fact, that typography and layout in eReaders is just not that good and automatic hyphenation is not perfect. Maybe we someday will have readers with a type engine like latex inbuild (could be difficult to make and difficult to use or change things like fontgsize in a timely manner) but until then it is a trade off. We loose some niceties in typography compared to paper books, but we gain things like control over font-size, family, line spacing etc. And we can read on a smartphone and a computer screen.
We don't compare in a vacuum. Kobos have some qualities as have kindles. And different people have different needs and therefore weight them differently. It doesn't work to single out one feature and make it the all important one. Because the next person thinks it is the most unimportant feature ever
