Soundproofing at windows: significance?

Hello everyone,

Unfortunately, I have not really been able to find out what significance the sound insulation rating of windows has in relation to the exterior noise protection compared to the bricks.
There is sometimes criticism of hollow bricks because of their poor sound insulation, as they only have a sound insulation rating of about 40 dB.
However, when I look at the tables of well-known window manufacturers, I find sound insulation ratings well below 40 dB. Only with special soundproof windows are values of up to 43/44 dB achieved.

What “sense” does it make to consider the sound insulation of the bricks as a criterion at all if these are usually better than the windows anyway?
Or am I misunderstanding something here with my "weakest link" way of thinking?

Best regards
ufr123

No, you understand that perfectly. Above all, the brick still receives 2 cm of interior plaster and 3-layer exterior plaster.

The reason why hollow cavity bricks are sometimes criticized for sound insulation is mainly because they are not suitable for multi-family houses. This is because sound noises are more easily transmitted from floor to floor within the house.

In single-family houses, it is not as serious.