No it doesn't.
This system is signing the revision id number (im assuming based on the video). There is not neccessary any connection between the signer and the revision id. There is no way to verify if the revision id was ever valid (typically revision ids are sequentially increasing numbers but there are edge cases where that is not true. And i dont mean censoring edge cases, although there are systems on wikipedia where pages can be deleted or revisions hidden)
So what does this system actually prove? That someone at a specific point in time signed an integer. Maybe that integer corrdsponds to a edit they like, maybe it doesn't. Maybe they never read the edit. Maybe the edit never existed.
This whole thing is seriously stupid. It is a non-solution to a non-problem. The problem they are trying to solve doesn't exist and even if it did this wouldn't fix it.
I mean hell, at the very least you think they would sign a hash of the edit instead of just an id number.