It really depends on how many leaves we’re talking; a thin, evenly distributed layer? Yeah that’s just mulch and is great. A thicker layer that turns slimy and dense? That grass is a goner. Area and species of leaves probably pays a big part I imagine. I have an area near a fence where the leaves piled up and were left a year and now there’s no grass there, even a couple years later (there’s a super embedded layer of decomposing leaves that’s blocking everything else out even after removing the bulk of the leaves)
Of course, there’s never room for nuance in these conversations.
I’m doing my part!