Its alright - Did bronze in Year 10
Does it help with confidence? I suppose. Is it fun? The camps are fun, and the other three activities are really up to you, so do something you like.
And to answer your question? big eh tbh. Its a nice addition on the resume, but not really relevant after you get your first job. Employers tend to care more about prior work experience over stuff like duke of ed post HSC. If you are doing the Gold/Silver award however, it can be used for some bonus points for Uni entrance I believe.
Do it for fun, its a good experience and a nice award/accomplishment to have. You can use it in interviews to highlight qualities about yourself, ie: "I displayed leadership in my Duke of Ed Award, which can help in the workplace blah blah"
But overall, employers/unis wont really care about it on your resume, its just an extra thing you can have if it comes down to a tight decision over similar candidates, but a lot of other things, like SRC/Prefect or other awards in things like sport/debating/chess etc do the same.