User blog comment:RoznosicielCiast/Least popular champions/@comment-4061583-20130124222714/@comment-5266525-20130126214820

A Deathcap gives you 100 AP and an extra 25% scaling on ALL of your abilities.

And besides, even if it is slot-efficient, why do you think Augment: Death is the only really used one of his upgrades? The other two really need some form of scaling buff.