Unless you or the tech is relearning the system everytime a tire rotation is performed it won't be accurate. You need to do the "GM Tire Dance" to relearn them everytime, most everyone doesn't do that (dealerships are maybe doing it depending on the dealer's quality).
Toyota's newest TPMS systems in some vehicles combines the TPMS and ABS system functions to determine wheel position without needing to do a procedure; which is pretty cool.
Honestly, I'm still iffy about TPMS; it's come in handy where I had a tire a bit low because I accidentally under-inflated it after a off-road trip and on a cold morning it tripped the system. I probably wouldn't have noticed it until much later when I would have checked tire pressure, but I probably would have caught it eventually.
I will note that LT tires will look fairly inflated even when very low on air; so you might have a nail in the tire and not even notice it visually unless you're checking tire pressure every day.