They can be done well but it has to be thoughtful.
Passageways in Hong Kong are popular, but that’s because the pedestrian density is so high they manage to fill both the skywalk and street level. The passageways provide shelter from tropical sun and rain, sometimes even air conditioning. And it’s a very hilly city anyways, so often you are picking between walking uphill on a plain sidewalk vs. doing it on a skywalk with escalators and elevators.
