Some choice quotes from the article:
[S]pent leaves that flutter to the ground aren’t a waste product. They are rich in carbon and play an essential role for the tree and the ecology it supports.
The leaves act as a physical barrier for soil, keeping it and its many microbes insulated, and also for the tree roots, as the wet mats of autumn leaves shelter the fragile top layer from the drying winds.
Many, many things live in these dead leaf layers: caterpillars of moths and butterflies, their chrysalises, beetles, centipedes, springtails, woodlice and spiders … and doesn’t the blackbird know it, rustling through the leaves?
No one loves wet autumn leaves more than earthworms, though. Sensing one of their favourite things, they start to work on incorporating them into the soil. Earthworms line their homes with autumn leaves, using them for bedding and then, because they are good housekeepers, they eat them as they break down.
Leave the leaves be: they are not a mess, a waste or a hindrance – they are life and vital with it.
Trees and their leaves smother life underneath them in forests. The leaves do eventually biodegrade and fertilize the soil and in the spring before the leaves grow back the forest floor is full of lots of fast moving, fast living greenery, but then the leaves grow back and usually whats left is stuff that gets sunbeams from breaks in the trees and some hardier species and saplings waiting for their moment to take over. Trees move in slow motion, but they are actually quite active and competitive creatures. Even once their grown their branches smack into each other as the wind blows and they grow competing for sunlight. Some small trees will just give you a little coverage and yeah you can ignore it and it will be broken up and blow away on it’s own, but if you have a big tree your hard will get blanketed.
A yard and garden are not a natural forest theyre artifically curated. Letting a yard be smothered by leaves might be good for starting the cycle that slowly turns empty ground into forest in my parts, but most people keep that yard space for activities, or for kids to run around, or for putting a garden in or something.
That said a few leaves wont kill you and you dont have to immediately run for a leaf blower or rake as soon as a single leaf falls on the yard to keep your grass perfect.