Its 4 mana for an unconditional board wipe
Kataki, War's Wage Affinity flat out loses to this if it's timely enough and doesn't have the Galvanic Blast, and can still struggle even if the timing is suboptimal
Planeswalkers are generally worth attacking, and then we come to the remaining categories: graveyards, hands, libraries, and lands
As you can imagine this wasn't that fun either
Bear in mind as well that if your opponent doesnt find a way to deal with Jafar on their turn, which is definitely a risk with their hand of seven new cards, then you can just sing A Whole New World again if you drew it from the last one
As an uninkable card with a cost of nine, there's an inherent risk in keeping this in-hand, but any deck that's designed to take a beating can quickly increase its viability