There’s a whole linage of arcade game button design, but you occasionally see keyboard switches show up in custom fighting game sticks.
Mice and trackballs often borrow from the whole universe of buttons to make their sculpted formfactors work. I feel like I’ve seen one or two with mechanical keyboard switches in them.
Like rockSlayer mentioned, they just bridge a physical connection between two pins and can technically be used anywhere a typical button could be. Keyboard switches are so optimized for their large square footprint and particular travel distance that they’re usually not the best fit for random industrial needs. You could make an elevator control panel out of key switches, but there’s probably a cheaper, more well suited button you could use instead.