Abyssal Scepter: Why is it still an aura?

Something I've always hated with Abyssal Scepter is that you essentially waste the aura if you're a long-range mage. As such, it becomes a forbidden item to purchase as because it'll be too cost-inefficient. Any time you're in range for the aura, you are too close to the enemy and will probably die.

So why is the effect still an aura? Why can't it take up Fiddlesticks' (live) passive and apply a MR debuff on enemy Champions you hit with spells? Is it not supposed to be accessible to long-range mages?