The Judas gospel would make one huge difference if it was accepted. It would dispel the centuries of anti-Semitic paranoia that were among the chief accompaniments of the Easter celebration until approximately 30 years after 1945, when the Vatican finally acquitted the Jews of the charge of Christ-killing.
Christianity, of course, has much to repent of in its treatment of the Jews over the centuries. Nevertheless, when the Church rejected Gnosticism, it was taking a step away from anti-Semitism, not towards it, because the Gnostics despised the Jews, the Jewish God, and Jewish Scripture. As Hyam Maccoby writes,
While anti-Semitism (in the sense of intense dislike of Jews) was not uncommon in the ancient world, it was probably among the Gnostic sects that the most radical form of anti-Semitism originated — the view that the Jews are the representatives of cosmic evil, the people of the Devil. (The Mythmaker: Paul and the Invention of Christianity, p. 186)Maccoby continues by portraying St. Paul — most unreasonably, in my opinion — as himself an early Gnostic. However, Maccoby's principal thesis is correct.
Gnosticism's intense rejection of Judaism seems to have been overlooked in the modern revisionist rush to anoint the Gnostics as a "healthy corrective" to orthodox Christianity. If the Gnostic version of Christianity had prevailed, Judaism might not have survived.