Yes, the roof tent in winter is a good idea. However, you should consider a few points in order to achieve the best possible result. First of all, the tent should definitely be weatherproof. It should therefore have at least one zipper and be made of waterproof material. A roof tent usually meets these requirements very well, as it usually has a robust construction.
Another important matter is the interior of the tent. Here you should think about whether the air circulation in the tent is good enough. The ventilation must also be right. Otherwise there is a risk of unpleasant surprises while sleeping! ;)
I'm often out and about with my tent myself and can confirm that it works extremely well - even in winter! One advantage of roof tents is that they are usually very easy to set up and take down. This is very practical, especially in winter, because you don't have to stand in the cold for long.
If you want to use the roof tent in winter, there are a few points you should consider. First of all, it is important that you set up the tent correctly. It is not a good idea to set up the tent near trees or other obstacles as snow and ice can fall from the branches. Set up the tent so that it is freestanding and has enough space for air to circulate.