Is insulation useful with Poroton bricks?

I am always appalled at how backwards construction is still done nowadays.

What is backwards about solid construction? I prefer to generate soundproofing through sand-lime brick/clinker construction rather than a little wooden hut with some insulation in between ;) . Yes, insulation is easier to build with your variant. But it is not cheaper than the classic brick house. Unfortunately, it is not cheaper than stone + ETICS. And your indoor climate must actually be a disaster:

PE foil sealed airtight

You live in a clad plastic bag? How horrible is that? Warning: The post may also contain irony

With the wall construction I have perfect sound insulation and very good thermal insulation properties

I would like that too, but: How good are both actually? Put the numbers on the table, please ;-) (Let's leave out the energy saving cost-benefit calculation for now, I would say, I was already cured back then during the house planning when switching from KfW 70 - those were the days! - to KfW 55, that was almost 10 months ago ;))