. . .the trees have begun to drop their leaves.
Leaves are a key component of compost. They make up the "browns" or carbon rich ingredients (the other component are the "greens" or nitrogen rich ingredients).
One of the roles that "browns" play is to help control the odors that might develop in a compost pile. I'd say that's a pretty valuable role!
So, from an ecological standpoint, fallen leaves. . .
. . .might just as well be like piles of dollar bills lying around for the taking!