I never understood it either. In my department everyone accepts the WFH days as “days off” but no one says the quiet part out loud. It’s even hilarious how everyone pretends they work at home but then know to not bother people who are on their day off. Even our boss is in on it. One time he told me to tell a coworker from another country to see why a non-critical server was appearing as down, so I told him no problem, but I think that the coworker is not in office, so he said never mind then he’ll do it tomorrow.