I'm on the East coast and I do mulch leaves with the mower for most of my lawn. However there are parts of the property where we have more trees and where leaves accumulate from being blown by the wind from other parts of the lawn. In those parts the lawn would probably die if I didn't clear the leaves myself.

However I also have honeylocust trees which drop loads of these large bean-like seed pods and these stems after the leaves fall which bunch up and can only be best described as like "wads of shaved pubic hair." I also have sweetgum trees which drop these hard, spiky seed pods that I also need to rake up. The mower can turn those into projectiles.

Really the best solution, in my case at least, would be to alter the landscaping in that area to something that would be unaffected by the leaves, but I don't have the time for that now. So clear leaves I do.

That's the smart way to go, decomposing leaves fertilize