I'd be interested as well. Of all the reasons, this (not fit for intended purpose) struck me as the only compelling reason that doesn't come off as an 'and also...' argument (ie: justificatios/rationalisation of a decision, post making one's mind up).

If I were to hazard a guess, this ability to follow descendents helps follow the evolution and intent of current state of code, given some previous state? (how did we get here from there and what else changed on the way).

In git that'll kinda sorta be possible with git bisect.