It varies - lounge access yes (Centurion Lounges, Delta, Eurostar), some of the other items like car/hotel status no but then it depends on which one. It can get silly, as an example Virgin Gold is meant to be for main cardholder but I'm already lifetime Gold so I had to mess around to have it allocated to another person on my account.

If you want additional Centurion cards beyond the standard 3 (2+1), they are 1100GBP per year.

This is the text on the UK Centurion portal right now for hotel status:
Furthermore, as a Centurion member, you and your first Supplementary Centurion member will be fast-tracked to the higher tiers of leading loyalty programmes around the world - without having to fulfil the usual qualifying criteria, such as numerous nights stays each year. Enrolment is required.