I owned multiple iPads and never found a compelling use case for them. I don't know why I keep buying them but they have been great computers for my parents so it's not like I buy to shelf them. Are there any use cases (apart from drawing maybe. I can't draw a stick figure if my life depended on it so that's not for me) for developers?
My iPad is almost exclusively for watching movies on planes. And it's very handy for that.
The original Surface RT might have had the best form factor I've used for plane movies - 16:9 screen with built-in kickstand. 16:9 is sub-par for basically everything other than tv/movies though.