MCU: 15 Most Powerful Items In Marvel's Phase 3

The immediate powers of Ant-Man's suit are pretty obvious: he can shrink to the size of an insect or grow to Giant size to become a "distraction" in battle situations (as in Ciivl War), but it's actually a lot more useful than that.

The shrinking mechanism means Scott Laing is able to telepathically connect with ants of any type, basically turning him into the head of a ready made army (all of whom are totally expendable, which is a devastating prospect for any enemy). Plus the process of shrinking bends the laws of science to amplify his power and force, so he's effectively a bullet.

And then there's the accidental powers he wields: if Laing over-uses the belt, he can travel into the Quantum Realm, effectively making his suit an inter-dimensional portal key, and marking him as one of only a couple of superheroes capable of that sort of travel (even if it's supposed to be incredibly dangerous to him).