Is the concern for the design and functionality of the space or for something else?

My kitchen is TINY, so my wall oven is right next to my fridge. It was necessitated by the space, but we've had no issues with it at all.

Typically you want to have counter space available for both of these appliances, however, it is done in kitchens where you don't have space or you want more open space. I have a large kitchen and we have double ovens at the end of a wall with the refrigerator next to it and counter space next to that. It works just fine for me!