A loom in Narayanpet carries several sarees' worth of silk at once, so a weaver finishes sarees in batches. The buyers rarely arrive in batches. One boutique in Hyderabad wants a maroon-mustard saree for a wedding, a family in town wants two in pink and purple, and a trader across the Karnataka border wants the rest.
On a personal phone that becomes eight chats and a notebook. On the API, each buyer's order carries its own updates: a photo when the saree comes off the loom, a dispatch note when it leaves, a payment reminder if the advance is still due. The shop's staff see the same thread, and the owner can see which buyers are still waiting.
None of that needs a broadcast. The one message that does, a new design sent to many buyers at once, goes only to the ones who asked for it.