[masklinn]

That would actually benefit the state (financially anyway) as it could just pocket the extra income.

But afaik in Germany if you’re officially non-religious, or your declared religion is not party to the church tax system, you just don’t get taxed.

[nicbou]

This is correct. The Church Tax is only collected if you belong to denominations that collect it. The state takes a cut on the collection, so Church Tax indirectly benefits other citizens.

On the other hand, it's pretty unsettling to be asked your religion when you register your address for the first time. The church in your home country can sometimes onboard you without your knowledge, and you end up paying the church tax. This happened to French and Italian friends.