Suppresses Weed Seed Germination
A light layer of clippings can shade out small weed seedlings—like annual bluegrass or chickweed—by blocking sunlight and physically covering seeds. While grasses themselves aren’t invasive in a well-managed lawn, weeds often are; mulch gives your desirable turf a head start.
I once compared two adjacent plot halves—one mulched, one bagged—and found the mulched side nearly weed-free by midsummer! That saved me countless kneeling sessions yanking seedlings.