Well, not quite; single-stage/two-stage trigger technology, as well as progressive triggers, have some benefits when applied to keyboards.
First, single-stage/two-stage triggers give you (with single-stage) a single smooth press with activation point somewhere in the middle, or (with two-stage) a consistent amount of takeup then a wall that you have to break through to activate the mechanism. So you can have the key pressed and resting on the activation point, and then press it the rest of the way when you want the input to register (for instance, if you're in a game and are waiting for someone to peek around the corner).
Second, progressive triggers, where pressing a little way registers a single input and pressing it all the way down/back types something fully-automatically. They're still mostly useless because the manufacturers refuse to put properly heavy springs in the switches, but the technology itself is ready for this.
It's certainly strange that it took 70 years from the implementations of these ideas in firearms to today's keyboards given the advantages of each mechanism are equally applicable to both, but that's the way it happened.