Imagine seeing these dogs running on the curb of our streets each carrying a basket, commanded by a neighborhood grocery store.
I think the running robots will have advantage over wheel based ones, which may have trouble climbing over curbs frequently found in my area.
The running robots will have better way of unloading too. When it reaches the front door, it can bend down, trigger a release mechanism of the basket door, and let the stuff slid out onto the door mat.