The reason this trick exists usually becomes much clearer the next time the oven gets turned on. Because ovens have a way of holding onto things much longer than people realize. Not just mess. Smell. Grease splatters, tiny food spills, smoke from roasting, something sugary that bubbled over weeks ago, cheese that dripped and burned, oil that baked into the bottom, little bits of residue that never got fully wiped away — it all builds up slowly.
And even when the inside doesn’t look especially bad, that buildup tends to linger in a way that becomes very noticeable once heat gets involved again. That’s usually when people start noticing the problem. Not while the oven is sitting there cold. But the second it heats up and the whole kitchen gets hit with that stale, burnt, slightly greasy smell that seems to come out of nowhere. And once that starts happening, the appeal of little tricks like this becomes much easier to understand.
Because deep-cleaning an oven is one of those jobs most people put off for as long as possible. So if there’s a simple way to make it feel a little fresher in the meantime, people tend to remember it.