Back in the days of design and testing, I recorded A LOT of times, temps, and data. And really.. in the end it didn't really matter from the user standpoint. Maybe on a WSM i'll glance at the lid to keep it 200-250. But over hours and hours, it doesn't matter. Doing a roast on a kettle indirect, it'll be plenty hot, just close it and let it roll. In an hour or so you'll be done with that 3 pounder. <----generalizations. I never temp burgers, dogs, sausage, most chicken pieces, small cuts.
So these days I just wait until I think it should be about done and I probe it with an instant read Taylor ($15). Close? Ok. I can start the sides on the stove, set the table. Maybe i'll probe a shoulder or a long cook once or twice earlier.
As pointed out by others, I just don't want to serve undercooked food is all. But really, the constant collection and monitoring and adjusting of temps are relatively meaningless IMO. It's data, it may be accurate data -but it's just data.