feddit.de is in this error state since quite a while now (over a month). The web interface does not work anymore, but connecting through an app still works (I use voyager for example). Most people have migrated away from feddit.de to feddit.org. I will do the same at some point, I just didn’t have the time yet.
It will be less efficient, yes. But it is still a net positive. If it is cheaper to build it there, you can just add more power to compensate for that loss in efficiency.
It will not be a 100% loss. For reference: the power loss of the transmission in the US is on average 5%. Let’s say it is double that, it is still very little in the grand scheme.