The Luger was the German Navy (and a few years later became the German Army) sidearm. It was designed to kill, and with use of the tangent sighting system and stock it could be used to lay down suppressive fire at distances.
The 9MM Luger outperformed the .38 in revolvers of the timeperiod, so would we say the .38 was designed only to "wound?"
WTM45,
WWI was trench warfare battles. While I have studied it some years ago including its significant battles, I don't recall learning about the 9MM being used in actual combat conditions. It was a war that saw introduction of the machine gun as battle weapon that kept opposing soldiers out of no man's land, the area between trenches. Since it was impossible to kill soldiers with small arms who were ensconced within trenches, artillery was perfected, which accounted for most WWI fatalities. Then, of course, the French invented poison gas as a way to get Germans out of their trenches. So gas masks were invented. And the Germans responded by creating their own poison gas. So if handgun were used in WWI, they saw extremely limited duty, certainly not enough to reach a conclusion about their effectiveness.
Some British soldiers did have handguns. But I have no idea how often they were used and if they were used, conditions of their use. The rifle was the primary battle weapons of all soldiers.
While the 9MM was issued to the German navy during WWI, I know of no account of their actual use in battle. Do you?
Finally, a battle handgun is not designed to wound. It is a CQB weapon where an enemy's charge has to be stopped immediately lest he's able to inflict carnage on his enemy. This was the essence of developing the .45 ACP. While no handgun is as reliable as a rifle in terminating an enemy's charge, some battle handguns are much better than others.
