The implementation totally broke the intent. You can't click NO. So it was useless.
They put even 1st party cookies on your PC ANYWAY even if you don't click "OK".
Also they never warn about 3rd party (the evil ones regarding privacy). Why is blocking that OFF by default in Firefox?
Simply BAN 3rd party cookies.
Also Google is popping up a giant contract you have to agree to unless you block their cookies.
Google are also somehow changing Firefox so when Google is blocked they are unblocked and you get their cookies back and then a day or so later their malicious multipage contract terms.