A lot of business travel often means working late at night after room service has shut down.
Having a mini-fridge in your room can be a lifesaver in these situations.
If your hotel charges for that mini-fridge but will waive the fee if you ask.
Hotel competition is tight, so asking for such upgrades and getting them free isn’t unheard of.
If they argue or won’t waive the fee, just indicate that you’ll be using a more hospitable hotel next time and the chances are that the fee will disappear.