Storing "empty" barrels with lees

I see this practice advertised in the used barrel classifieds, but I’ve never heard the rationale behind it. It’s done by reputable wineries, and I’m sure there is a good reason, but I’m unclear on the concept. Anyone know?

Too lazy to clean them out? Sounds disgusting to me.

Are they offering to pay you to take the barrels away?

I believe this a way to do pied de cuve.

I don’t think that’s it. They will be advertised for sale as holding lees plus a heavy SO2 solution and inert gas.

I’ve heard of several wineries that do this. The “recipe” I heard was, drain out the lees as well as possible, do not wash, then gas with SO2, bung, cup or tape. Before you want to use the barrel again, wash it well, then it’s ready.

That’s what I have gathered, but I’m unclear on the rationale. It’s pitched as though the remaining lees have a function in preserving the health of the barrel.