is it worth it? I guess so, if ur going to go to usyd anyway then you might as well accept Dalyell. but don’t make your uni decision based on Dalyell as a factor it is not important at all.
what Dalyell does is it replaces 6 credit points of OLEs (typically online broad units) with 12 credit points of Dalyell units (generally pretty annoying broad bs units) - this does mean you miss out on one elective space which is a thing I guess. you also get access to a $2k scholarship for if you go on exchange which is actually pretty nice because it means you can basically go on a free holiday with one of the experience OLEs
basically you might as well take it when u start at usyd and then drop it later if it doesn’t work nicely with your degree, but don’t let it influence ur uni decisions