A smaller switch tester for when you only have a handful of switches. Or when you want to demo to your friend only your favorite tactiles. Or just to have on your desk to play with during meetings. 

Switches fit reasonably snugly to use as a fidget but maybe don't throw it in a backpack or purse. With keycaps on, switches can be removed by pulling on them but the box design helps with pushing them out from the inside unassisted and also means no pins sticking out anywhere. It also just sounds nicer/more realistic You can also throw in some dampening foam inside for funsies (but I'd scale it to be a bit taller).  

(If you're curious the switches are (when the first image is rotated clockwise slightly):