Laura Rooke:really want to watch full-length films on their phones when they have a 2.4" screen
I certainly do.
I have a 2.8" screen and held at the right distance it workd perfectly well for full screen divx films. Usually I have the screen within my line of sight while I am using the PC, so I use for films which I have seen before rather new films.
We have 32" - 40" screens at home, but we watch those screens from varying distances which effectively make those screens smaller. Have a 2.8" - 5" screen sitting at a right distance and the effective screen size can be similar to your home TV screen, thanks to perspective.
The majority of videos that I watch on my screen are music videos and clever adverts. As their average lengths are only a few minutes, holding my device fairly close to my face to watch these fine and again makes the effective screen size more than ample to see all of the detail on offer.