Well, there's 2 kinds of stealth...there's "strategic" stealth (for lack of a better term) where the plane isn't detected, and the only indication it's there is the destruction of the target. Then there's "tactical" stealth (again, I'm just coining these on the fly) where the target can be detected on EWRs or other "detection only" radars, but is unable to be tracked by tracking radars and therefore no RH missiles, AAMs or SAMs, can hit it.
Unless you're on a mission with deniability, generally speaking it doesn't matter if they can see you if they can't hit you. Of course, the old adage is if you can see it, you can hit it, but that was in the days before guided weapons.