I don't think it is of any use on CV, but it does have som benefit for some children. However, if you DD doesn't want to do it, you can only tell her the benefit, and let her decide.
DS1 is doing it, he has been looking forward to it, and I think it is a good opportunity as well. For learning new skill side, he does the same as before. He has been learning 2 instruments, and he also does 2 sports. For volunteering side, he now helps in a club for primary school children, which I think is good for him. The best part for him is the expedition side, he has attended a few training session, and will start to do a couple of warming up one involve camping, walking and navagation in the forest. We start to do some walking during weekend, as I think he need to gradually build up resistence. They need to walk 8 hours a day in the formal session. And he is in the same group with a few of his friends, that's quite important too.
I think is Dofe is an opportunity to put lots of good activities together, and as parents, it would take some effort to arrange these sorts of things, but now it is all arranged by school, which is great.
Some friends' children are not doing this, but they started to do some jobs, like deliverying papers and other part-time works. I think it is the same. These all help our DC to become mature, independant and caring.