Not in many if not all circumstances in which I'm required to readback QNH. Just fat, dumb and happy below the transition altitude in an area maintaining the altitude I've reported when requesting an inbound clearance, which request includes 'with [e.g.] Charlie'. ATC looks and sees me squawking that altitude at that location, then proceeds to tell me I'm identified, give me an inbound clearance ... and the QNH. If it's so important for me to read that QNH back, notwithstanding that ATC can see I'm where I say I am (both laterally and vertically), it seems to me to be at least as important, if not more important, for ATC to confirm that the crew of a fat jet about to take off has received the bit of ATIS information that says the runway end has been displaced.