Combo Priests will love this card. Jepetto could draw you Velen and Malygos, bringing the total damage of the Mind Blast spells to 40 from both copies.
This combo alone guarantees the high demand for this card. But since it's neutral, Jepetto will be used in many other combo decks. And who knows what wild players will use it for?
The potential is boundless and the value is extremely high in Jepetto Joybuzz.