Panels are cheap, and the single-phase inverters they are using are too.
Even with the odd placement, they are going to yield a few hundred watts per panel on sunny days. Since it’s so low most of it will be going directly to household consumption.
This doesn’t move the needle much globally speaking, but it’s also a tiny investment and (especially in Germany when even in sunny days the carbon footprint of what comes out of the grid is horrendous) it significantly lowers household carbon emissions.
Orientation doesn’t matter as much as you’d think on overcast days. And this is Germany. Also, transmission is a thing. So unless your “perfect world” also includes perfect weather and upgraded physics, you are just not really making sense.
In the end you’re just yet another person ginning up excuses for inaction by distorting facts. And god knows we good plenty of those.