Balance question - Spell Binding

[Settemio]

I am not very good at this game and I don't claim to understand balance, but I am especially puzzled by Spell Binding. Why does it have such a LONG cooldown? Why does the AI want to Spell Blast it?
If this were a PVP game, I would be pretty happy if in the Very-Rare-Spells phase of the game (late game), my opponents were spending a huge amount of their casting skill just to give themselves a boost to research, which is kind of what I see when I look at Spell Binding.

[Desertfox]

Spell Binding is potentially one of the most powerful spells in the game. It potentially gives you 5 chosen Very Rare spells, even from schools you don't have books in. It shines as a catch-up spell if the enemies are ahead of you in research. The cooldown is probably an attempt to make it less powerful.