Your inventory is scattered across locations
You might run a central warehouse and still not know what is actually sitting on each store's shelves.
Store 4 has a surplus that Store 9 needs today, and neither one can see it. Short-dated stock expires in one location while another writes a script it can't fill. Every store orders, returns, and writes off on its own, blind to the rest. The group carries the cost of all of it.
It doesn't have to work that way. The stock one store can't move is stock another store, or another pharmacy, needs right now.