As someone who works Area in the UK, I think it's amazingly stupid. Given the amount of points that we have introduced to allow level by restrictions without a distance before a certain point, e.g. level BEDEK instead of 40 before OCK, and the number of airlines reporting their STAR on first contact to reduce RT congestion, I fail to see how telling every aircraft the QNH will help matters.
Given that our radars can only show flight levels, i.e. something at 6000 ft might well show 6,200 on the radar isn't going to help either, unless some clever sod has thought about how to filter that.
I can't see the benefit, I know a few American carriers report climbing/descending to an altitude, but they are so few and far between and it only takes a second to clarify.
As far as I can see, it's someone in an office somewhere who is trying to keep themselves in a job, god knows there's enough of them knocking about in aviation