Why isn't Enspell Damage affected by magic attack bonus?

[Supersun]

It's magic in every other sense, but it isn't affected by magic attack bonus modifiers.

I mean if we keep getting cloth sets that give us magic attack bonus, shouldn't our class at least get the full benefit of magic attack bonus?

Would it even matter THAT much?

You would need pretty insane amounts of MAB just to raise it a few points of damage.