[nobody_nothing]

Full disclosure I'm not a production designer, but have worked in the art department on some smaller film productions.

These individual parts are likely used to build larger props that a production can't otherwise acquire. For example, assembling a cyberpunk plane interior, or the control panel in a time machine.

They can also be scattered around a set where those individual parts would belong (like a mechanic's studio) to make the space feel real and lived-in.

Lastly, they can be used for close-up shots (with just a little bit of production design built up around them). This is a lot cheaper than renting an entire interior.