Yes it is worth it. BF is the BEST form of nutrition for a baby. However, it is not the only form and some people choose not to BF. A BF peer supporter is not going to do anything for those mothers.
However, some people want to BF and some of them who were unsuccessful would have been helped by proper support.
I do think that part of a peer supporter's role is to recognise when BF is making you or your baby ill in any way and sometimes to advocate the cessation of BF.
BM can make a difference, but I suspect that the benefits are sometimes a little overegged, in the same way that formula manufacturers overegg the similarities of their product to BM.
It is bound to be better as it's what we are designed to drink. It is not, however, going to prevent all allergies, make you fantastically intelligent, turn you into a successful entrepreneur or guarantee you're not going to ever get cancer.
The majority of us make our choices based on intelligent reasoning. It's a real shame that isn't respected by others and that every conversation about bf/ff turns into a bunfight.