Y’know one of the things that was bigged up most about Gravity Falls was the journals. The whole series was about collecting all the journals, finding out who the author of the journals was, trying to solve all the mysteries that surrounded Ford’s journals
And in the end they were basically useless. They almost never contained any information that helped the Pines family at all. They were even destroyed at the start of Weirdmageddon and it had basically no impact on them.
But there was one journal that DID help the Pines family. We’d seen it on a regular basis for two seasons and never paid any attention to it. We assumed it wasn’t important, but it was.