Ahahaha now it gets interesting.
The previous actions may have all been to simply give John credibility for this moment.
Not only that, but this might prevent Terezi from scratching disk 2???? It might change what happened with Vriska too but since she's probably going to try to fight Jack who knows. Terezi felt really bad about doing it though, so it's very possible. Ghost Vriska x Ghost Meenah would still happen I think because ghost selves, although John's retcon power is a thing. It's starting to become clear why it's being shown inbetween chunks of John's retcon journey.