With ship from store, retailers use your stores as mini warehouses. The total available-to- sell stock increases dramatically. Slow moving items from certain stores can be sold to optimize stock positions. This decsreases lost sales, and increases revenues for the retailer.
With ship-from-store to consumers in the same city, delivery options like same-day delivery and bike-delivery options are possible. This has significant durability impact and positive effect on the retailer brand.