They aren't perfectly usable if they've been used. Semiconductors are kind of like toothpaste - if they've been used, you don't really want to buy them.

This is largely because the cost of any individual component is so much less than the cost of a finished assembly, or the cost of a defective assembly. Inserting used components into your manufacturing process (unless they're very high value or rare parts), is asking for trouble.

These components need to be stored properly to be effectively assembled, and you'd never be sure of why the used one were thrown out. Especially as many types of damage or degradation would either require very substantial and specific testing rigs, or else be challenging to identify in the first place.

Putting them inside a vehicle isn't a viable option from an safety or economic perspective.