You are right that this does not prove all videos of earth are fake, but wrong in assuming that @NothingSirius makes such a claim (such a claim might have been intended, but that is not obvious). This does prove, however, that creating fake simulations that look real is incredibly possible. At the very least, it should lead people to think twice about images they see and question the validity of "photographic evidence" for the round-earth theory. For the sake of fairness, I will also state that this can be used to shed skepticism on flat-earth attempts to photographically prove the flat horizon.
TLDR: take pictures with a grain of salt, since they can be easily modified or flat-out fabricated
