Yes, but if you can use less gas for electricity generation you have more for the other uses. Germany has other sources of gas besides Russia (e.g. Norway). The goal isn't to completely stop using gas at all, but rather to reduce dependence on Russia who only supplies 30% of German gas.

Problem is, without nuclear power, they will have to resort to generating power from natural gas instead of using that gas for heating, which will in turn have problems compound.

If there's no gas, most homes can heat with electricity. Turn on your oven, your gaming console, your TV, open your fridge's door, etc. Also as I understand it, it's much easier to do rolling blackouts on electricity than on gas, so gas will be more likely to fail for a long time than electricity.

Most industrial processes can be stopped without endangering people.