Not strictly true about why directors delete stuff.
Sometimes stuff is deleted from films as the movie studio say its too long.
I have heard stories of directors having to cut scenes they really love because some movie exec wanted the film to fit into an 80 minute timeslot!
Also of course censors have their say in what scenes do & dont make the cinema.
I stupidly bought the X-Men 1.5 DVD which supposedly had all the deleted scenes added back in but it was a fucking rip off!
All the scenes could be shown in the context of the film but the film would pause,go to the cut scene,then jump back to the movie,there was no tidying up of the scene or attempt to actually make the scene blend in so often you saw the same thing happen twice because the cut scene wasnt trimmed.
Another idea that I find ridiculous is the new "Superbit" DVDs which provide no extra features at all so they can apparently give us even better quality sound & picture.
Oh come on,how many of us are gonna notice "even better sound & picture"?
DVDs are pretty much damn near perfect anyway so "even better quality" is a fucking joke!