This has been my question too. It seems so obvious and back when I used to anxiously await every dev update I seem to remember them saying "we're experimenting with things" and "we chose real time renders for very intentional reasons" but it doesn't look like we've seen much of a payout from that choice yet. Considering the current option is basically just switching between videos of faster or slower speeds of the animations anyway, just doing what other games do with actually switching between faster or slower speeds would be fine.
Maybe we'll get lucky though and they'll actually make it worthwhile eventually. I know from going through reddit for (what for me) was a complicated way to unlock the camera shortly after the game first came out, I saw the animations look reeeeeal bad from other angles. They'd have to do a lot of reworking to fix those, and at the current dev pace, that wouldn't happen any time soon.