DriverStore is basically a component store for driver files. This way, multiple driver versions for the same device can be preserved, and you can switch to an older driver if needed. Driver sets can be cleanly removed, since everything is self-contained. There's a space penalty in you might have duplicate files in each of the versions. Which is a big problem for NVIDIA drivers since the rendering DLL's are massive.
Copying the DriverStore doesn't really work since the overhead info is stored in the registry, so you can't recover drivers by pointing a command to the backup copy. You need to do the PNP export commands to make old driver files re-usable.
