The idea
When people register cars it is so the Police can trace car owners if they break the law. There is a high standard of proof and the Police have high standards.
People do not give their details so some licenced ex-nighclub bouncer can make a trumped up allegation and harass them at home. But that's exactly what happens. Any "person with a valid claim" eg a car park attendant or clamper – can write to the DVLA and get the owners details for a can registration number.
This WILL be abused. Owners of expensive cars will find themselves burgled. Attractive women will gain stalkers. Grudges will be pursued.
There is an altenative – the DVLA should never disclose an address but should instead forward communications for a modest fee, say 50p.
Remember, convicted hammer murderer Levi Bellifield was the owner of a clamping business. He could have got your home address without any questions.
Why is it important?
People give the State private information for State purposes and expect it to remain confidential.
Handing out addresses on an industrial scale without any proof is an appauling erosion of privacy.