I think convertibles are extremely useful for students. You got a normal laptop for writing papers and do other work things and you got a tablet to read through pdfs and study slides. No student wants to carry around two devices when one is fine, it is just more mobile.
People that complain that it is worse than having two are people that sit at home and don't need the mobility and usually enough cash because they already have a well paid job.
Apple will not jump on it because they said they wouldn't and while they correct their mistakes (iphone 6) it usually takes them a while. OSX would need to get enough touch externsions to make it usable pdf, slide, video consumption device in tablet mode. That wouldn't require too much work but there is no such work going on. It would show in early dev builds of newer OSX version before they release such notebooks.
I think zhenya got a point with the keyboard. Apple probably thinks it isn't elegant enough this way. They will leave that market to the Windows crowd. I think for students it is a lot better. Where I to study now I would definitely choose it over a Mac. With that and Office just being so much better in Windows and having the combatibility, there is no competition. But I am no student anymore.