That's a simple (good) question with a not so simple answer. I've thought about this quite a bit since this thread started. Here are my thoughts.
Condensation is caused by one simple thing, the surface reaches dew point temperature. Dew point temperature can be reached by either lowering the dry bulb temperature or raising humidity.
Relative to condensation, insulation does one thing, it allows the temperature inside to be kept above due point more easily (eg using less fuel).
Inadequate or poorly installed insulation, and/or 'thermal bridges', can create cold spots where due point is reached (eg, on certain walls, or areas of walls).
Humidity is increased by humans simply living, and by the type of fuel being burned for heat.
So, the idea is that a composite structure would have less thermal bridges than a metal frame structure, and hence the inner walls would be easier to keep above dew point.
Imagine worse case where you have a closed (well sealed) area, cold outside temperature, poor insulation, a few people in a small space, and are creating additional moisture in the space by burning propane. (Propane combustion creates water vapor....a non-trivial amount).
