It would only make sense if they didn't tell anyone about it - ie just instructed the wardens to behave like non-robots and allow 10 minutes, but didn't actually announce it as a policy. Once you say, 'you've got 10 minutes extra - that's official', it's pointless. As ttt says, they've just moved the line.
But actually, focusing on this 10 minute thing is a bit of a distraction - the complete package, aimed at cracking down on local council bullying and profiteering of motorists, is worthwhile. Some of the other things are ..
// guidance for councils reminding them they are banned from "using parking to generate profit"
a right for residents and businesses to demand - by a petition - that a council "reviews parking in their area"
new powers for parking adjudicators so they can "hold councils to account"
protection to stop drivers being fined after parking at out-of-order meters
a ban on the use of CCTV "spy cars" except in no-parking areas such as bus lanes and near schools
//