As Tamriel's leading wizard, I have often been called upon, usually by individuals of royal birth, to impress them with some demonstration of my magical skills. When I ask what they'd like to see, they nearly always reply, "Throw a fireball! A really big one. I'd love that."
This just shows how poorly educated Tamriel's aristocrats are about the magical arts. The Flame spells have their uses, of course, but the true magical scholar gives pride of place in his grimoire to the Shock spells. For whatever reason, manipulating arcane lightning is easier than forcing magical flame, and it can be employed for a greater variety of effects. Here are just a few:
—The mage can cloak himself in an aura of lightning that will turn aside certain physical and magical attacks, as well as shocking nearby enemies.
—Lightning can be cast on a surface in the form of a rune that will explode if touched or after a certain delay.
—A wizard can cast a bolt to a nearby target and then instantly "ride the lightning" to that destination.
—And, of course, lightning bolts can be cast directly at enemies in a number of variations.
It is possible, I suppose, that ways to manipulate Frost and Flame will be discovered that make those elemental magics as flexible as Shock—but if I haven't discovered how to do it, who else could?