It’s a German military term from WWII. The Wehrmacht, from near the end of WWI were innovators in what is now known as maneuver warfare. It gelled for them as what we know as Blitzkrieg tactics, and progressed on to modern doctrines of Maneuver Warfare the US Military. And it’s a darn sight better than the previous style of static trench style warfare. Static defensive warfare is great for slaughter on both sides. It’s a strategy you employ when you care not for losses because you are either more numerous than your enemy and care not for the impact of mass casualties, or weaker and want to survive a war of attrition by hoping your enemy doesn’t have the stomach for it.
But as to schwerpunkt: emphasis or critical point of a battle. Is the translation. In battle is the point on which you apply maximum effort in order to achieve a decisive result. It can be the turning of a flank or a break through in line. Or it can be defensive, like holding a defensive position in the Wanat battle or the effort of the 20th Maine in the Battle of Gettysburg when, on the far end of the Union left swung out like a barn door, to keep that edge from being turned, then swung back in and surprising the enemy with a bayonet charge after their ammo ran out. The swing of that barn door was the swing of the battle, and the war.
But I just like the sound of the word. Schwerpunkt. The Germans contribution to Modern English for word that there is no real English equivalent is entertaining to me. Like schadenfreude, angst, doppleganger and kindergarten.