I assume the key aspect here isn't to provide an alternative storage mechanism (since the cookie laws aren't actually about cookies themselves, but rather stora

I assume the key aspect here isn't to provide an alternative storage mechanism (since the cookie laws aren't actually about cookies themselves, but rather storage), but rather to provide a mechanism with clear and centralised user control. Users must opt-in, so its good in the eyes of the laws, but the advertisers get the benefit of easy legally-compliant tracking when a user allows it.