>>530004469
Or if you're not an idiot you can assume that the material written by Toby Fox to promote Toby Fox's game is canon to Toby Fox's game until there is a reason to believe otherwise
He just doesn't want someone who buys Deltarune in 2030 to feel like they have to go dig up a decade old ARG to get the complete experience. Toby makes stuff like this for the Truck Freaks who want to know every bit of information he's willing to share, but everything that's actually important to understanding the story is or will be part of the actual game.