If it doesnt add anything I dont really care. I will leave the dead leaves from the plants I am growing in the tank but I think I will pass on adding them lol
They add tannins, although Indian Almond leaves leech much more than the oak and beech. Tannins will darken the water but they also help soften water and they have anti-bacteria and anti-fungal properties as well.
I've only seen a couple tanks that I liked how they looked with dried oak leaves in them.