The NYTimes had a piece on the fading away of extra features which used to be included on DVDs. My wife and I are long-term subscribers to Netflix, back in the days before streaming, and we (or I at least) enjoyed most of the features, particularly the director commentaries. The best movies seemed usually to have been models of teamwork: a lot of talented people working together for a common goal. No doubt that was an exaggeration, or more kindly a rosy colored look back.
The commentaries varied widely: some directors would narrate the action on the scene--very boring. Others would use the action as the launching point for little stories, discussions of technique, particularly the more cinematic types. Some would make a point of praising the work of both the actors on screen and the members of the crew behind the scenes. Some series, like Breaking Bad, and Mad Men, would have multiple features and often two or more commentaries per episode.
I'll miss the extras.