One of my favourite use cases for my Pebble Time requires wearing it whilst I'm asleep: I use it as an alarm clock. I'm awoken by it vibrating on my wrist. I find this a much more pleasant way to wake up than a normal audio based alarm. Being able to snooze an alarm without having to open my eyes or reach out of my warm bed and without waking my partner is brilliant. I would be annoyed by a watch which I had to remove each night to charge.
I've got an LG Urbane which I charge every morning while I'm showering and getting ready. It's on my wrist overnight for sleep tracking and the morning alarm. I can agree with your judgement on alarms, but my experience of an OLED-based watch differs from what you seem to expect :).
30 minutes is usually long enough, although I usually leave it longer than that because I'm still doing stuff. The last 5% charge is a lot slower, but isn't really necessary -- it doesn't matter if the battery drains from 95%--45% rather than 100%--50%.
