How do you evaluate the ISOWOOD concept?

We are currently looking for a general contractor for our construction project and came across ISOWOOD Haus. I find the concept very interesting, but I wonder if it really delivers what it promises. Especially the fact that they build without a vapor barrier and without controlled residential ventilation, and whether that can work, I can't really assess. Maybe you could give me your opinion on this or have even built with ISOWOOD and already gained a few years of living experience.

It will probably work. Wood fiber is not quite as susceptible to moisture and is vapor permeable. However, I still wouldn’t build without ventilation, because fresh air has to get into the house somehow.

The wood fiberboard is only on the outside. Inside there is an OSB board and gypsum board installed on it. The OSB board is basically a vapor barrier, isn't it? Or can moisture also diffuse through it?

Yes, OSB is vapor-retardant. The crucial difference compared to other structures is that the wood fiber between the studs is not susceptible to moisture, but mineral wool is.

Then I still do not understand what any moisture in the insulation has to do with the ventilation system. If the OSB board is vapor retarding, moisture in the insulation would not be carried away by the ventilation system. Or am I making a mistake in my reasoning somewhere?

We are currently looking for a general contractor for our construction project and came across ISOWOOD Haus. I find the concept very interesting but wonder if it really delivers what it promises. Especially the fact that they build without a vapor barrier and without controlled residential ventilation, and whether that can actually work, I really can’t assess.

That sounds like a general contractor search conducted (unnecessarily in your case) without me ;-)
You can choose to want controlled residential ventilation or not, but it should definitely not be "replaced" by a wall structure. I would at least keep my distance, if not run away, from a general contractor who told me his magic wall makes controlled residential ventilation (mind you, if one even wants it) obsolete.
In your position, I would not go searching without experienced support (I already pointed to alternatives to me).