Economically it is very simple and beneficial to Germany.

There are two foreign-policy angles:

The Eastern-European states (mostly Poland and the Ukraine, but also the Baltics) are constantly afraid of Russia. Especially to the Poles it looks a bit like Germany and Russia diving Poland between themselves in WW II.

That's the good foreign policy opposition.

Then there's the bad one: America. America wants to sell liquid gas from fracking.

That gas is more expensive, so Germany builds ports for those LNG ships, but also the pipeline.

America warns that Germany makes itself dependent on Russian gas, but that's bullshit. Germany can switch over to American LNG at any time. The infrastructure is there. As soon as Russian gas stops, gets too expensive, or strings are attached, Germany can almost instantly get American gas.

The only problem is: America wants to sell their expensive gas right now.

And so the impose sanctions, not against Germany, but against everyone remotely connected to that project. It sounds like an exaggeration, but they literally impose sanctions on some janitor working for a port that let a ship enter which was working on that pipeline. And the mayor of the town the port is in. And everyone else.