So I figured the square option would be better as it utilizes cupboard space more effliciently. However, I came upon a drawback: with the square food container, the lid may fall in when placed at the diagonal. This happened and it smashed the base. Sic transit gloria mundi. Of course, if the base had been a little stronger…
The same can never happen with a round container as the lid can’t be positioned at an angle where it falls in.