There are many reasons to visit and spend a beautiful holiday: to discover a new culture, to see a different environment, to visit unique sites, such as the Kakadu, Kimberley or Uluru, to see animals you will see nowhere else roaming free - kangaroos and other marsupials, to visit the Great Barrier Reef, to admire the Sydney icons: the Opera House, which is a UNESCO world heritage site, the Harbour Bridge and the largest natural harbour in the world, to experience a relaxed lifestyle.
As to your finances, just state what your budget is and how it is covered (bank account, travel cards, any accommodation already paid for.)