The physical card is sufficient to prove you have permission to drive. This code is for them to check how many points you have on your licence and what for. There used to be a paper counterpart to the card which showed this which they withdrew a few years ago.
In reality I've never been asked for the code when renting cars (outside the UK), the physical card seems to generally be sufficient for the hire companies.
In reality I've never been asked for the code when renting cars (outside the UK), the physical card seems to generally be sufficient for the hire companies.