Indeed. And one of the reason for the why, beside just understanding the context and getting a more complete picture, is to allow further developers to add code

Indeed. And one of the reason for the why, beside just understanding the context and getting a more complete picture, is to allow further developers to add code at the same place because it was meant like that in the original code. Great comments helps to know if a new module should be written, or if the addition fits nicely in the existing picture.