I live in Berlin, I have some friends that bought some panels just because they could. I'm considering myself even though I don't get a lot of sunlight on my balcony. I only pay about 60 euro per month. But these kits only cost a few hundred euros. So why not? If it saves me 10 euro per month or so, it would earn itself back in 3-4 years under ideal circumstances. It's not a huge saving obviously.

> My concern is what happens when there’s a power outage? I’d then be feeding power into a system that’s “denergized”.

This is Germany, they would have studied that topic thoroughly. In short, the certified inverter that you must use for this would indeed shut down in case of a power loss. This is usually called "anti-islanding protection" and not an optional feature for this.