There is a specific kind of tired where the deciding is the problem. It is half past two, the screen has stopped making sense, and you have twenty minutes you could spend either horizontal or standing by the kettle. You have run this comparison a hundred times and never once reached a conclusion before the twenty minutes quietly disappeared. Two slices and one tap gives those minutes back to you.
A nap is the option that actually pays something back. Twenty minutes with an alarm set, and you come out slower for a few minutes and clearer for a few hours. Coffee is the option that works faster and costs nothing up front, but the bill can arrive at bedtime if the cup lands too late in the day. One borrows from tonight, the other repays a little of last night. That is the whole trade.
The wheel does not know how you slept, when you last had caffeine, or what is on your calendar at three. It is a tiebreaker for days when either would do, not a health tool, and if the slump turns up every single afternoon the honest answer is more sleep at night rather than a better spin. Set a timer if it says nap. Keep the cup small if it says coffee.