> It is vastly more complicated to find targets at 1500 miles than at 20.

It's true but they are so cheap that launching a whole bunch and/or improving them incrementally is possible. Yeah they are for stationary targets mostly, for sure. And of course their sounds and relatively low speed does make them somewhat easier to shoot down with short range AA guns and can have automated acoustic early warning system (it's like a flying lawnmower or chainsaw).