What do you mean by “many people” and “internal positions”?

I do not think that there will be many internal appointments to begin with. When we talk about internal appointment, it is usually given to officers who have shown potential and interest to take up the role. Usually within 1-2 years of doing that, he/she will go for interview to be officially appointed. The internal role given will allow the officer to try the role out while preparing him/her for the interview since it provides better clarity on the responsibilities and gives one things to share on during the interview. Some schools do not practise that. But given that now officers can only go for interview at geo 4, it may be a way to sustain their interest.

If you are referring to other duties like level rep, case managers etc, they are more of roles for additional contribution towards the organisation. If you do it well, you may be noticed and subsequently given internal appointments or identified for ST track.