This is a Gnostic gospel, and they have their own cosmology that breaks with the mainstream Judeo-Christian traditional entirely. By their account, there was a singular creator god, but there were also a bunch of lesser gods. The ancient Jews inadvertently started worshiping one of these lesser gods, mistakenly thinking he was the main guy. Jesus came to set all this straight, and Judas was the only apostle who really figured this out.
Jesus is a very different character in these. He usually comes off as an asshole. In particular, see the Infancy Gospel of Thomas, where a young Jesus kills his friends with his mind for not sharing the ball: www.youtube.com/watch?v=1gA8hXDJocQ
Is it more fantastical? Not really, but it’s not marching in the same direction as the rest of the story. It’s the difference between Captain Picard’s mom dying when he was young when we saw him dream her as an old woman, versus Captain Picard walking on the bridge and kicking Riker straight in the nuts for no reason and then lighting up a joint. One is a contradiction, but not really that important when it comes down to it (unless you insist that the material is absolutely true, in which case you have other problems). The other is so far off from the character’s normal behavior that we have to assume something is wrong.