One difference is that the state also provides title to these assets, with all the legal protection that this does (or does not) imply. Another difference is t

One difference is that the state also provides title to these assets, with all the legal protection that this does (or does not) imply. Another difference is that this contact information does not, AFAIK, include recipient-paid [1] contact methods such as mobile phone (including text) and e-mail. Also, methods such as phone are generally considered far more intrusive that, for example, paper mail. [1] nowadays this is mosty nominal, but we're not quite at zero