@dkemppai, I think you will find those extremely useful when you are in a position to do something about it, like changing fit classes of taps. You won't like them so much if you only have one set of drills and taps (or whatever) because you're stuck with what you have, and once you have gauged it, you'll know the real truth.
Y'all know me and I like pulling legs, but I mean it- these are critical tools for fitting parts. The problem is once you check, you'll find things, then you'll have to fix them. Such a slippery slope! I have no doubt that having the gauges will eventually lead to discoveries in producing better fitting threads.