There are a lot of these courses going around in Australia, and they're not worth anything. I did a one-year hospitality and tourism course that included a module of flight attending in it. The module in NO WAY covered safety and security measures. It covered service skills and interview skills to go for a cabin crew position. Now that was very helpful to me.
These 1/2/3/4 day courses are a waste of money. 399 seems like a lot for 4 days. You don't get a job afterwards either and I don't think you will be a step ahead of others who haven't done it. I was a step ahead with my certificate (it was done in an expensive private college) because it taught me heaps of skills I could bring in to the role of service, the interviewers when I got my job told me it looked well on my CV. I reiterate that my course was far more intense and involved a lot more modules.