You're not alone (reply to first post, didn't read the rest yet).
I've tried a bit on these mobile devices, and found them pretty inefficient to use. Anyway, I don't even know for what exact reason I should use one of these devices, so I don't use one, and I don't feel I'm missing something.
GF has a smartphone and I can hear her cursing a lot about the thing, mostly user experience related. Sometimes I have a look at it: Most web pages (no matter if optimized for mobile or not) are confusing or distracting or spitting ads into your face. Apps appear to be somewhat more useable, but the user interface is often laggy and doesn't provide useful feedback on your actions. I've tried to read books on a Tolino, but was very disappointed by having to move my fingers in strange ways just to turn the page, and you don't get instant feedback if your movement was right or just caused something else that you don't want to happen. I want real (clicking) buttons to turn the page.
So these things really do not provide anything that would attract me, and I'm fine with not using one. In the history of computing (yes, I've seen all the ZX81 and C64 stuff in "real time"), there were many improvements in user interface, but also several steps back: one of them beeing todays mobile devices, another the 16:9 screen format and mirror displays - I don't use my computer screen to watch movies, 16:9 and pitch black is fine for the TV, but no good on a computer.
To stay on the original topic: What is all that facegramlinkedxing stuff? Never seen (OK, that's a lie, GF uses Whatsapp, so I've seen that at least), never missed anything of that. Had a linkedin account that I deleted when M$ took over linkedin (did they really, never bothered about it?), but that was pretty useless anyway, so nothing lost, but gained instead: No more annoying mails from them.