Well, quite often when editing I will create subclips from the master clips of material I think I may use. However, I frequently want to go back to the master clip to look at material that is adjacent to my sub-clipped stuff. That is just what happens in editing.
The way Premiere Pro seems to work now, I am forced to reload the master clip and using timecode reference points "manually" search for the adjacent footage. If clips are just pointers to media, why does PP unlink the subclips from the originals?
Does that answer why I need this match frame flexibility?