I'm guessing it gets hot in a tank. Somewhere it said they pattern the controls of modern war machines after the 'joysticks' for video games because that is what is familiar to progressively more pans-ified generations of Americans emerge from their parents' basements. The new ones are probably air-conditioned.
They're hot. When I was stationed in Vietnam I was made gunner of the crew. Only because I was a newbie and the long timers aren't going to sit down in that oven.