My 1976 Chevy Blazer had 2 keys. The ignition key had a square head and the door key had a round head. https://picclick.com/Chevrolet-Corvette-Camaro-Nova-Chevelle...

It is (or was?) quite common to have a valet key, which would start the car, but not open the trunk or glove compartment--and in some cases would limit the speed of the car to below e.g. 30mph, in case some valet tried to take the car for a Ferris Bueller-style joyride, I suppose!

Mercedes-Benz's have a pop-out metal clip that can be used to lock the glove and trunk. It's designed to be extract with a simple press so that dropping you car with a valet doesn't require turning off the car to remove it.

Clearly the lock isn't meant to stop a determined intruder. It's more of the "Locks are for honest people" type thing to indicate that you shouldn't be opening the glove or trunk.

My Supra has the valet key, which doesn't open the glovebox, but opens everything else - it's slightly shorter than the main key, so probably trivial to pick the glovebox lock anyway. The smart keys that limit the maximum speed are a nice feature - I think some manufacturers advertise them as being particularly suitable for learners!

Chevy's too, I wonder at that every time I drive my 70's 4x4. Ironically? I have the parts and plan to update it to remote locks.

And one for the gas cap too

My Ford has one key, works on everything, of course it is a truck and has no power locks or windows.