Mixed use zoning is good for specialty retail like niche/designer clothing. Also even for things like groceries people (like me) will be willing to pay a slight premium for being able to get those goods from a short walking distance.

Ah, but the more niche it is, the more likely they depend on car traffic to bring their customers in.

I'm fortunate to live within walking distance of a supermarket. It's nice to get fresh produce and things that we run out of or need on a whim. A little Ace Hardware store serves in a similar way. It seems like the fairly sizable population of retirees in the nearby apartments provide these stores with a lot of business.

I don't expect those stores to have everything, but they really reduce the number of car trips that I make.