Actually, I think that using VR to watch movies in constrained spaces (i.e. airplane seat) would be a fantastic idea. Having just been on a long and boring flight, I would have given quite a bit to watch a movie on a "big screen", even if it was virtual.
Big screen playback of YouTube and Netflix through a smartphone would offer a much better experience than watching a limited selection of titles on a postcard sized screen on the back of an aircraft seat.
Given that you're going to own a smartphone anyway, an accessory that's an order of magnitude cheaper than high end VR seems like it has a place.