
Umpteenth reason to preserve youtube videos: they can get 'replaced'
from the comments "when you showed that the lonely island video is more zoomed in now, it reminded me that on their podcast a couple of weeks ago they off hand mentioned that when youtube was doing 4k enhanced music videos they got a secret link (and made it sound like it was not part of standard youtube studio/admin) that allowed them to completely replace the video file that was uploaded without changing the url or the views of the old video and the only requirement was the length stayed exactly the same. so my speculation is their higher quality export was cropped a little differently when they replaced the video"
this is one more bad outcome possibility if you care about the original, on top of video being reencoded with a new codec, or the video deleted, age or country restricted, or turned into premium-subscriber-only (to the channel).