I think the main problem is you need the accreditation if you want to apply to immigrate. As I understand it even if you are from overseas and study at a Australian university you would still need to get the accreditation to apply for a visa.
I believe it also exists to provide a framework around CPD (continuing professional development), but I'm not sure how relevant this is to our industry.
"Temporary Residence Transition stream
If you apply for the Temporary Residence Transition stream, your skills do not need to be assessed because you have already worked for your nominating employer for two years in Australia.
You must have at least vocational English.
This stream is available only to people who hold a subclass 457 visa. People who hold other 400 series visas may qualify to apply for a permanent residence visa through the Direct Entry stream."
[1] http://www.immi.gov.au/skills/skillselect/index/visas/subcla...
However as an employer, I've hired a bunch of people from overseas on a 457 visa and never thought to get them to talk to the ACS. I don't really care if your university degree has been rubber stamped or not. (And if you can write code, I don't really care too much about your degree)