>> opposite of a privacy issue, since it's keeping your data in your browser.

In a way instantly accessible to the host site. Data I wasn't really consulted about. Data I might not be comfortable sharing every time you ask for it.

This whole law about disclosing cookie use, which I will agree is not necessarily a good approach to the problem, does nevertheless exist because of a problem - People getting tracked, followed and profiled without their permission. Website operators and browser-makers seemed to be complicit in this. Some website operators seem to think it's their god-given right to do whatever they want in the browser on my computer...