I honestly don't understand what the big deal with Ternion Attack is. I know in theory that the three attacks, each at slightly reduced damage, add up to more damage than a single attack when they all hit the same target, but then what is the point of Arcane Lore? From what I can tell, Arcane Lore only does two things: speed up the projectiles (which is nice) and increase the radius of the spread (which seems counterproductive if you want all three to hit the same target). Why does everybody swear by Ternion with Arcane Lore? Would I be better off just ignoring Arcane Lore, or does it do something that I am unaware of?

On a side note, I also find Ternion Attack to be the most aesthetically boring spell in the game, even if it is as good as people say.

It does what you just said yourself - increases the projectile speed. That is a blast, since you can spam more projectiles that way. The higher projectile speed the better. You just hold [Shift] and click around, and watch enemies die much faster.

It does for ranged attacks what increased melee attack speed does for melee weapons.