Amazon is expanding its same-day grocery delivery service to 1,000 cities and towns across the U.S., the company said Wednesday.

While the retailer’s same-day delivery expansion leverages its enormous reach online, its fractional brick-and-mortar presence remains a central liability, industry analysts said.

Amazon is now rolling out a service where its Prime members can order their blueberries and milk at the same time as their batteries and other basic items.