There is no benefits truly. By the time it takes for it to break down, and turn into Mycelium. You need a few weeks. And you need 2be on enzymes but the risks of mold go way up with leaving leafs on your sub unless you got good air flow. Which should move all over your plants body.
Dead leafs can attract bugs. When they die they release a smell that will attract munchers + they make more you got pests.
Generally sometimes if I see old leafs and good Fungi you leave it. You notice the dif. Mold is green, and bud rot is bad.. but? There's lots of benifical fungi. I had FPP. and lil yellow mushrooms grew and lots of yellow fungi down the sides of my pot. At the end of ripening the plant had eaten the entire lot. What was left was remnants of yellow Fungi that turned white and last bits of Mycelium was left
Killer bud. But, back to your point. Look for good Mycelium reaction from dead growth. Generally there's a nutrient in every line that helps break down broken roots and so ppl cam reuse soil. Just something to break down the old dead growth to beni fungi and that's it. (Oh and top up your soil. As reused soil clearly won't have nutrients. So I use Mega worm on my reused soil. Or worm castings ppl use. Its like staring of with new soil. Much cheaper also when you go through 1000L per c
