I needed a switch like this for a recent project, so I designed it up (literally still hot off the mill)! A spring loaded pin gets retained in the body to turn the microswitch on/off and turn your project on/off. A few applications immediately come to mind: high altitude balloon activation, safety power down, quick deploy instruments, detachment activation. I couldn't find anything like this out there other than people using 1/4" stereo plugs or 3D printed parts.
So what do you think? Would this be useful for anyone other than my narrow niche of instrumentation? Demo video: