LB for me there is a difference between reading back "standby" (the controller is using it to specifically ask you to not reply) and reading back the QNH which has a safety implication if this is not correct.
I personally find confirming to the controller that you will not reply, (when they have just told you not to reply), mildly annoying, whilst reading back QNH has at least a safety check value so is not a biggie (for me).
I know some people get annoyed over calling WACs "WAC Charts" and ATMs "ATM machines" and this issue feels the same - I reckon there are other things that really do deserve me twisting my knickers over - eg people who are wrong on the internet...