Besides the tank kits, I also have kits of certain WW1 soldiers. But I noticed that the early German and early USA soldiers from Miniart have soldiers at a walking pace, each with a commanding officer with his pistol drawn. I was wondering why the latter, since presumably they are not in an actual fighting, or about-to-fight situation? The Osprey books I have don't mention this practice.
MiniArt don't make any WW1 figures. I presume you mean ICM? They cover all the major combatants.
If by "early German" you mean the set wearing pickelhaube, 35679, the poses of those figures suggest to me an "advance to contact" or patrol. In other words, looking for trouble or expecting it. It would be usual to have sidearms drawn in such circumstance. These figures are from the time before trench warfare had set in, when more traditional infantry fighting and tactics were still practiced.
The 1917 US infantry set are clearly somewhere behind the lines, and the officer has a camera not a pistol. The 1918 set are clearly in action, so drawn sidearms would be usual.
Pistol shooting was still taught by most major armies at that time as a deliberate discipline: like target shooting. What we would now consider as combat pistol shooting did not really come into common practice until WW2. There was no quick draw, no shooting from the hip or 2-handed holds and sidearms were generally carried in fully-flapped holsters with buttons or snap fasteners - or even in wooden flip-top holsters. This made drawing the weapons in an emergency too slow, so carrying them drawn when there was any likelihood they may be needed would not be unusual.
