The church tax is not the only income for the church. It receives a large amount of money from the general tax, exactly to perform restorations of old buildings

The church tax is not the only income for the church. It receives a large amount of money from the general tax, exactly to perform restorations of old buildings and cultural heritage. Even if you deregister from the church and therefore do not pay direct church tax, some of your tax kroner will go to the church anyway.