And that may be why the video that Amazon released Tuesday emphasizes snacks - a category in which it has introduced its own private brands. That could be largely due to the fact that many consumers still want to choose their own food. By comparison, some 46% of customers favor online ordering and store pickup services for other retail categories, Sargent said.

The consulting firm's research found that only about 28% of grocery customers say that the ability to order online and pick up in-store is important - the lowest category of all those Magid measured. Still, in some ways this is a curious move, considering that grocery customers aren’t exactly clamoring for pickup services, according to Matt Sargent, senior vice president of retail for Frank N. Amazon helped stoke a thirst for swift delivery that many consumers never knew they had, and now curbside pickup appears to be heading to a similar level of competition among grocery retailers. Wal-Mart has been expanding its own grocery pickup services and experimenting with various formats, and many traditional retailers (which have offered delivery and pickup services for years) are also expanding and marketing such services.

Amazon fresh pickup