The reason the course has a higher cut off is because you definitely get to go on exchange and you have compulsory language courses (which a lot of people find difficult at the university level). It is a specialised arts degree.
Career prospects obviously depend on your major but copied and pasted from the unsw international studies site:
Upon completion of the program you will have the opportunity to access a wide range of stimulating and high-profile professions. Our graduates can be found in industries worldwide including:
International business
Government agencies (including foreign affairs)
Investment banks and other financial institutions
NGOs and the UN
Journalism and Media
Tourism and Trade
Law
If you're worried that you might not be able to find a job or haven't really got a career path in mind, you could always do a double degree and combine international studies with something else, or go for a slightly less specialised degree for greater flexibility in case you change your mind.