Oh, yeah. An early use of smokeless gunpowder. Changed the nature of tactical land warfare. Used to be the smoke from muskets and cannons gave away their position. Smoke buildup on the battlefield also created a literal "fog of war," causing units to get lost or disoriented and making it impossible for officers to give visual signals. Those problems didn't exist at the battle of El Caney.
"Some would say that extended meaningful conversation is a thing of the past. But they'd say it more quickly." (Tom Morris)
Hotter climates are less advanced because they don't have to keep moving to keep warm and has nothing to do with inate ability and that's why Europe is technologically advanced and all the warmer places had to follow because they were cold. This doesn't have to do with the war just the places conquered by Spain are hotter and Mexico is a bit corrupt.