In my case Youtube, Netflix, Twitch, as well as web browsing.
And also "everywhere I move about in the house", not only in bed.
I have zero use for it as a "productive" tool, but it's the best media consumption device I ever had, it has replaced my laptop for every use aside from creative/office work and gaming.
It doesn't do everything, but for what it does it's a great device.
I can see the problem for Apple though: if not for a cracked screen, I would have no reason to upgrade my 2+ years old iPad Air 2, since it is still more than good enough for all of the above.
I genuinely don't understand the use of tablets in bed.
I tried for a few weeks to use my iPad, but if I loosen my grip at all, I end up with an iPad smacking me in the face.
I went back to resting my 15" MBP on my chest, screen angled towards my face (of course). Then I can just put my hands behind my head and relax.
If you prefer to lie on your back, an articulated arm mounted to the headboard might work; I have one of those, but ended up not actually using it - by the time I'm actually dropping off, I don't want a screen glowing in my face.
I haven't really looked yet, but if there's an art class app that guides you through drawing exercises, I think I would take the leap.
I swear if I could afford to be retired today, I could keep myself busy for the rest of my life with stuff like this. My Dad retired a couple of years ago and I think he's bored much of the time. It drives me crazy.
I'd also buy a nice watch.
I'm a little tempted, now, by the iPad Pro and the Pencil. It sure would be more comfortable and convenient to retouch photos that way than with a mouse or a trackpad in Photoshop. But I can hardly justify dropping most of a grand just for that, and the other use cases I no longer have - especially with a 13" rMBP in my satchel, there's really not enough point.
That Pencil sure is nice, though.