(Extreme bias as a dropout of Comm/BBIS)
Depends on what you want to do in the future. BBIS is a very focused vocational degree, even moreso with 2 IBL placements, which means you're very locked down to certain business analysis roles. You won't learn much else, i.e your programming skills will be far too weak for technical roles, your knowledge of business too weak for business roles. It's very much for those who are "I want to get out of uni ASAP to start working", and odds are you will find a job (100% of those in the IBL stream gain employment after graduation seems like).
Commerce/BBIS will widen your horizons away from IT somewhat, depending on your Commerce major, and you will learn much more in an academic sense. However, I believe you will lose your IBL place (As the interview you took would only apply to BBIS single), and be forced to take an interview later. And of course, you'll have to be at uni for an extra year.
^Master of Business Information Systems is fail - it's for internationals to get jobs here. Caulfield IT in general is terrible.