Oh, I KNOW I've been had--but I still make better coffee (but I LOVE hers--it means I didn't have to make it! )

That chemist is full of it. Besides, he can say anything he wants. If my tongue is happy with the coffee, I'm happy!

Two things happen when coffee sits just after it's brewed (on a plate that isn't hot enough to boil it off)
1) the convection currents even it out. you can (should) stir it if you don't have time.
2) there's a slight smoothing of the flavor as some oils evaporate.

Of course, if the warmer is too hot, the coffee gets burnt tasting, so if you like it blistering hot, wave it, or drink it fast.