I've seen it on Air Canada (or Red or Jazz, or whatever it was called that day), and it actually worked quite well. They offered to rent tablets for people who didn't have devices.

I suspect managing the streaming server isn't going to be much more complicated than managing the old wired content sever... On the other hand, not needind kilometers of cables for entertainment, not needing to maintain them, makes a huge difference for the airlines. This is not as simple as pulling a cable in your house, planes have crashed because of fires from bad maintenance/install of cables, including cables for entertainment.