One of the most fundamental roles the mentor plays in the development of a scientist is the introduction to the subfield. Making the trainee known to other scientists who make up the field. Publication is key. Proper crediting during seminars is another. Sending the trainees to meetings and introducing them around to the key players is good too.
As I said, in my view this is fundamental. Inescapable. Science is a human enterprise like any other and therefore interpersonal relationships matter. A lot. Even if they are not supposed to, we are unable to escape our biases related to "knowing" and "not knowing" other people.
My question for you Dear Reader, is whether you were Introduced to a subfield as a trainee. Did your mentor(s) make a specific point to enshroud you in a field? If you are a mentor, do you go out of your way to Introduce your trainees?
(If applicable, feel free to tell me that this is a mark of backwater, BunnyHopper dominated OldBoyzGirlz backslapping subfields and should be rigorously uprooted.)