The thermometer came from the fear of wasting great meat.
A new cut, a different thickness, a hotter grill, and suddenly timing becomes guesswork again. That is stressful when a good steak or brisket is on the line.
Accurate temperature readings help us stop hovering over the grill and start cooking with confidence. It is the tool we wanted before ruining expensive meat taught us the hard way.
When the food is worth protecting, we would rather trust the temperature than a lucky guess.