I tried this when I first got a house. The leaves decompose and you end up shoveling a layer of mud off your waking surfaces. It also becomes incredibly slippery when wet. A dense layer of waxy oak leaves can be like walking on ice.
He's saying to leave it on the yard to break down, if you do that it turns to slippery ass mud eventually, and guess what people like to be able to walk in their lawns, if we're sweeping up the entire yard so that we can use our yard without it being slippery and muddy from decomposed leaves... congrats you've just fucking reinvented the rake and leaf blower
