Massive building vs. Prefabricated building

Massive always the fortress (whose ETICS unfortunately cannot even hold a lamp, but whatever).

I would by no means describe stone houses with ETICS as "massive": they are usually built from "load-bearing interior walls as exterior walls," but even with a Wonderbra, a 17.5 cm wall remains a 17.5 cm wall. If already a "wall" made of pure stretcher bonds, then at least one stone thick, please! - but in my opinion, that is popular nonsense.

Analogous to External Thermal Insulation Composite Systems, prefabricated house wall panels could actually be called "Thermal Insulation Integral Systems," since basically an insulation between rafters is placed vertically—just something to "let sink in."

The longer I read in this forum, the less motivated I am to write posts. But I liked yours!

If I made you happy, it was worth it—because for a moment I was actually tempted not to send the post at all: hardly anyone wants to hear the truth (that the question of which stone is the stone of the wise is only hallucinated relevance); the audience is mostly "calibrated" (or better said: miscalibrated) to the truths "Faction X is right" or "Faction Y is right." But nobody— not even me, hehe—at least not as long as it is linked with "or." Because, as one man's owl is another man's nightingale—and it shall remain so.

The "nice" thing is: granted the only true answer to the question "which wall building material" has been found—then we cannot happily and contentedly go home like Piggeldy and Frederick. Instead, the drone goes on: heating, ventilation, hot water preparation; wire mesh panel—hedge—gabion; did I actually mention this month that I prefer two single gates to one wide gate? *duck and run*

Indoor climate, we can't really imagine what that means, good air is sleeping with the window open..

Huge plus for the open window! And the construction of forced-ventilated Tupperware boxes is being promoted. I'd much rather have a design that allows good air even with temporarily closed windows. Besides temperature, for me, humidity, particulate matter, smell, air movement, type of heat source, and low pollutant levels play a role. That's what I call indoor climate.
We trusted the wooden construction to be better. There is no claim to "correctness" in this; the OP asked for reasons for the decision.

Phew, it’s getting philosophical again... The wall construction doesn’t matter for ventilation... Because no matter the wall construction, you have to pass a blower door test anyway... In other words, the ventilation demand, whether manual or automatic, is exactly the same.

Your timber construction is just as much a Tupperware box as any other modern house. Unfortunately, pretty marketing phrases don’t help there The air quality is not a bit better or worse, you have to ventilate just as much or as little. Whether you want to ventilate manually or automatically is a matter of personal preference...

If something affects the humidity, it’s the living habits (drying laundry etc..), or to a very small extent the interior plaster. The wall construction has exactly zero effect, how could it, ...

Your timber construction is just as much a Tupperware box as any other modern house.

He spoke out of ignorance of the construction - better to philosophize instead.
A blower door test does not have to be carried out.

That is of course unfortunate for you, because with a Blower Door Test you can often find weak points and construction defects quite well. Regardless of the test (you are right, it is not mandatory, but has mostly become standard), it is legally required by the Energy Saving Ordinance that the building envelope is airtight ... test or no test. Either your envelope is airtight by definition (or as you would say, Tupperware), or your builder is not adhering to current laws....

...or we want it that way, do it that way and are allowed to do it that way.