Amazon Fresh is easier to automate. I was surprised the pushed Whole Foods delivery in the first place, they were basically using the instacart model where a personal shopper grabs everything, very labor intensive.

The deliver straight from warehouse model has strong potential to be more efficient than a grocery store, even with free delivery.

Sell more Prime memberships and get a larger marketshare for Amazon Fresh which they can then monetize more.

It's a bait and switch like the original Prime membership. Offer really great deals for members at first then start jacking up prices once they're hooked.