Why did old PCs have key locks? [LGR Retrospective]

Retro computer cases often had a locking mechanism, complete with a key that came with the machine. But what exactly did these do, where did they come from, and why aren’t they so commonplace anymore? ● Consider supporting LGR on Patreon: ● Social links: ● Music used in order of appearance: “Club Noir 2,“ “On Your Way“