“Passive House is considered the most rigorous voluntary energy-based standard in the design and construction industry today. Consuming up to 90% less heating and cooling energy than conventional buildings, and applicable to almost any building type or design, the Passive House high-performance building standard is the only internationally recognized, proven, science-based energy standard in construction delivering this level of performance. Fundamental to the energy efficiency of these buildings, the following five principles are central to Passive House design and construction: 1) superinsulated envelopes, 2) airtight construction, 3) high-performance glazing, 4) thermal-bridge-free detailing, and 5) heat recovery ventilation.“ - Nickelsass

So it’s not just resistant to fire, it’s also much more energy-efficient and preserves temperature better.

Would the insulation also make it sound-proof?

And it looks nice. The only problem is I wouldn’t be surprised if it’s very expensive and/or difficult to build.

EDIT: People are saying it’s technically <20% more expensive, but requires specialized, skilled craftsmen and takes longer to build.

If energy prices increase and climate change become a concern, and as new architects who are taught new techniques come around, I can see these being widespread in the future. But for now, probably the only people getting these are people who care enough to sacrifice some money/time/flexibility.