Everything that I grill, I do by feel. I've done that for enough years that I know what a good steak "feels" like.
I'm too new at this. I can poke and prod big slabs of meat cook after cook and try to remember which "feel" came out a certain way, wasting time and money on bad cooks or I can take objective readings and assign my own subjective definitions to them as a way to learn while still enjoying good food.
That said, man is an intelligent beast and so long as the technology is accessible to make the task easier and more reliable, I'll probably take advantage of it.
22.5" Weber Kettle / 32" Master Forge Charcoal Grill / Modded/Restored NB Bandera