I think BA are best off letting passengers buy their own though really for 'normal' routes. I would imagine finding somewhere onboard to store them all would be an issue on most aircraft. Not mention union protests (if they get upset about hot towels in WT+, can't imagine they'd be happy with this). Then there's the issue of who is responsible for all these ipads (cleaning, maintaining etc.)

Personally, I find the screens in CW and new WT+ to be satisfactory. Plus they're specifically designed for aircraft and don't leak light into the rest of the cabin on night flights. ipad and laptop screens can be very bright, giving the area around them a similar 'flashing' effect to that of when you go past someone's house at night when they're watching television in the dark. Not what you want in such an enclosed space.