The 1080p/24 file uses LESS bandwidth for the same file size, therefore better image quality with the same size download. Google for details... This is why Id rather had a 1080p/24 download than a 1080i/60.
Secondly, if I have a 1080p display compatible with the native 24hz signal, why would I want to send it 1080i/60? Id rather avoid the deinterlacing, period. 24fps is the native framerate of the movie.
What I get at 1080i/60 is a frame rate conversion from the native 24hz, potential reduction in image quality (3 gigs at 2 hours of 1080i/60 is most likely not going to look as good as 3 gigs of 1080p/24 at 2 hours) and my display has to deinterlace. 
I agree with your statement, or at least part of it, but its not the whole picture.