Its definitely worth it to use all available space.
Still, it definitely cannot generate enough to bring you through the german winter.
Some example numbers I have read: A 10kWp solar system that generates up to 1,400 kWh in a summer month will only provide about 200 kWh in December.
You can get more power in summer by using a vertical bifacial panel positioned E-W.
And if you position it N-S you'll get slightly less power than a standard setup, but it'll be less concentrated in the summer, and also spread through the day more.
