Commentary, behind-the-scenes features, bloopers: What did we lose when we said goodbye to DVDs?

One of the things I enjoy about the Classic Doctor Who DVDs and Blurays are the production subtitles - almost every episode has production notes/commentary as a set of subtitles that provide background information on the episode and often the specific scene on screen. No idea if this is made available on Disney+ (which now has the rights to Doctor Who).