Gatekeeper is strongest when it was rezzed this turn, so it would combo with cards that allow you to derez your own. Cards that help you get more activations from the rez strength ability are needed to help combo.
Bioroid Efficiency Research makes it so if the runner does break through, you get another shot at the rez strength.
Divert Power makes something cheaper while you get to trigger this rez strength again.
Test Ground allows you to fire the trash ability, derez Gatekeeper, and then re-rez Gatekeeper with unexpected strength.
Plus, Gatekeeper is cheap and might give you some recursion of used cards if you can catch the runner flat.
Is it for every deck? No. But it might have a place in some.