Full rafter insulation roof or insulation on concrete slab

Insulation on the concrete ceiling and thus no full rafter insulation - here is the answer from my general contractor on this topic: Honestly, I'm not so enthusiastic about it. The stage area then becomes a cold zone. This is only limitedly usable as storage space. If slightly warmer air enters the attic through the ceiling opening in winter and meets the cold air on the underside of the roof, then there will be condensation at this point. What do you think? Is he right?

This will definitely become a topic for us as well. If the price is the same or even cheaper for the wooden beam solution, we will definitely prefer it. We have also had good experiences with thermal insulation between the rafters so far, so ..... "never change a running system," even if one can see it differently. Currently, we also benefit from this solution because we have been able to arbitrarily adjust lighting at various points, add additional outlets, etc., and all of this is easy to implement up to the installation of lamps, built-in parts, etc.; all of this would be difficult or impossible to do with a concrete ceiling. To what extent you then add insulation between the beams of the intermediate ceiling and/or make it walkable with OSB or similar, you can still decide. For me, a concrete ceiling between the upper floor and attic would feel more like a disadvantage, even if I were given the possibly more expensive concrete ceiling "for free."

When everything is finished, it is a huge advantage.