The problem with conventional non-guided or unaided rocket artillery or ground to ground rocketry is that it's extremely inaccurate, even by conventional artillery standards which can have a probable error of several hundred meters. Currently all US rocket artillery uses GPS "aided" GMLRS M31a1 rockets which have a probable error of only several dozen meters. Unguided rockets or missiles are generally only used as suppression and mass effect weapons which need to cover large areas, usually entire grid squares (square kilometers). Rockets are much more susceptible to meteorological forces than conventional artillery, which is why they aren't used unless under certain circumstances or conditions. The key to rocketry is accuracy. With wire guided, GPS guided or aided rockets, targets can be pinpointed and neutralized from much greater distances than standard artillery with extreme precision down to even only several meters.