When I buy online I have to wait for delivery, but at least I don't have to go looking for stuff in 20 different isles only to find out the thing I needed is in a completely illogical place, or deal with all the people there.
This concept combines all the disadvantages of physically going to a supermarket with all the disadvantages of buying online. Amazon's concept actually improves the physical buying experience.
I don't want to speculate but it would help if a french gentleman tells us his experience.
Not being able to take your stuff home is a little annoying, but depending on where you live it can be almost necessary to have groceries delivered. In Paris many buildings don't have elevators at all, or very small ones that can hold at most two people and not many bags. If you live on the 5th floor you're happy to get someone bring the bags up the stairs for you.
I could imagine using a reliable service again but, so long as driving to the store and shopping is straightforward, ordering online for delivery isn't something I really need.