Detection range and BVR

In a situation of F-16C facing F-15C, (assumed both being armed with the same version of AIM-120 AMRAAM). An EAgle driver might be able to detect an incoming F-16 as first due to superior detection range of APG-70 over APG-68 but still he has to approach within effective launch range to achieve a kill, thus being exposed to a risk of incoming AIM-120, as well. Of course, the presence of the F-15C won’t stay unnoticed with functioning RWR on the Viper.

My question is, what real advantage does superior detection range of APG-70 bring to the Eagle driver?