Whether one is pro nuclear or not, I think it makes sense to look at the specific situation at hand. Was it a mistake to shut down all nuclear reactors while not pushing for more renewables and replacing all gas and coal plants first? I think so. Should the last three remaining nuclear plants be kept online? I don't think so.
Germany's main source of heating is gas and yes, gas is used to generate electricity, so nuclear can reduce gas consumption. However, only about 10% of gas (see edit) is used for electricity and Germany has enough electricity. In a worst-case scenario, those nuclear power plants can help stabilize the grid, but they are not needed in general.
The downside is, that they were already in the process of being shut down. They now need to undergo new safety checks, the fuel rods are nearly spend and this will cost 100 millions. Money which can be spent better.
This winter also isn't predicted to be particularly cold, so the full gas storages in combination with the soon opening LNG-terminals will suffice.
EDIT: I made a mistake, 10% of electricity is gas.