this is not new to me as im based in the US

1) screen size: a tablet will be ideal, but it stays at home when i travel for work, and i will have to fight with my wife for it during our leisure trips

2) unsecured device: my experience is they provide a latch for your device somewhere near where the screen would have been. your device is not secured, and i frequently see devices falling. it is especially dangerous during turbulence because all they do is instruct you to securely hold your devices, and adherence is dismal. i guess it stays that way until some mishap happens

3) draining battery: i do not like draining the batteries of my devices while on flights. i dont want to be monitoring my battery levels and sometimes you just fall asleep. i do not want reach my destination with almost flat batteries. it can be a pain; sometimes you just want to leave the hotel or sometimes you want just to rest