Isn't it a benefit for all subscribers to get all answers ?

Look, some people may have a similiar problem like asked to the list. Now they get
all replies to the post and see the subject. Whoeever is interested in will read
it (and will get new knowledge probably), all others can delete it immediately.

Isn't this the intent of such a newsgroup ?

A reply-to-all is an add-on I also use rather frequently (and I receive as well).
In a particular point of a following discussion I reply only to the sender (and
s/he to me as well).

Regards, Andreas Schmidt, CSC, Germany