Hi.
By "Schlauch" I mean the living/dining area with the dimensions 426*976. The bay window (you mean as a protrusion, right) just breaks up the living room a bit. I agree with you that it doesn't really have any functional benefit. But I have been in many such houses and it always seemed to me like a long corridor. We always liked some kind of bay window or similar and wanted to somehow incorporate it.
But as you already say, it's expensive bought space. That's why I'm here looking for help and alternatives.