I imagine installation costs are also substantially lower since the panels rest on a much simpler structure. Cleaning the panels should also be easier in this configuration. I wouldn't be surprised if these findings lead to vertical solar systems becoming a popular option, especially in places as far from the equator as Denmark.
The output can also be timed for better value (for example, increasing production in winter vs. summer, or peaking early and late for N/S aligned modules.)
Combinations of different orientations can smooth output over a day or year, which could reduce the mismatch between module output and inverter capacity.
