A 2TB HDD is much cheaper than making a film-print, so in terms of economy, digital wins. But I've seen both beautiful and really bad film projection and beautiful and really bad digital projection - I went to see a French film in a cinema on Leicester Square in London last year and it was the tiniest screen with worse digital projection quality than a 720p data projector a friend of mine used to have - truly horrible but then I also saw some films in digital on huge screens, where I wouldn't have been able to tell it wasn't a perfectly pristine early generation film print (if it wasn't for the obviously digital Czech subtitles) and those were only 2K, so I imagine a high quality 4K projection could be amazing.