Typical answers include: cheaper, faster, most accurate, none of which would pass a technical smell test. On reflection, many might say they want calibration to tell them if the item to be calibrated is any good or not while not defining what ‘good’ means from a technical point of view.
Those who are unable or unwilling to make the call will usually revert to some technical standard or specification the item was ‘apparently’ made to and leave it up to the lab to take it from there. This can be a very expensive way to go and provide you with a lot of information you may not be able to use effectively. Such standards relate to instruments and gages when they were new so the tolerances in them are for the maker of them, not necessarily the user of them.