Honestly sounds like a waste of time. My grinder works fine at room temp. You're just adding another step for a tiny change you might be imagining. Coffee is already complicated enough without turning your kitchen into a lab.
Your grinder works fine at room temp because you haven't tried the other way. I measured a 20 second faster drawdown on my V60 just from warming the grinder with a hair dryer for a minute. That's not a tiny change, it's the difference between a sour mess and a balanced cup. You're leaving a lot of flavor on the table by ignoring the physics of how heat affects brittle coffee beans. It's one extra step that takes less time than preheating your mug.