Definitely, there's no way the AI will hold onto Ball Lightnings until they can be fractaled. If it could be programmed to, it would be scary. Assuming the AI empties its hand before fractaling, that would be 40 damage + 5 for the original. Two fractals and two thunderbolts = death.
120 is a lot of cards though, especially without hourglasses. Rainbow will draw through it quickly, but this might take a while. I guess it makes it easier though, like Hermes, who would be spamming another Destroyer every turn if he had less cards.