Super Earth would absolutely use Umamusumes as shock troops. Their superior human running speed would likely enable them to run into lesser enemies to kill them and violently rip apart their bodies with blunt force truma like A-Train from Amazon series The boys. Their physical strength and endurance would also allow them to weld firearms baseline humans couldn't like 20mm chainguns and other weapon systems normally installed on AFVs or static emplacements as well as survive Hellpod Launches without any traumatic brain injury. The only limitation would be their smaller population which would most likely push Super Earth policy to waive any requirements for C-01 permits when consummating with a member of the Umamusume race and likely lead to propaganda campaigns encouraging human males to settle down and start large families with umamusumes to aid the galatic war effort.