Our understanding is that it definitely can be used as an alternative to unfair dismissal laws for staff earning over the $109k salary threshold. Although there has to be a case for an Adverse Action claim.
Adverse Action seems to be a bit of a legal minefield which is still being navigated by the specialist law firms, so whatever your view or understanding may be, it may not be the view of the courts. In other words there could be considerable uncertainty for employers.
Many of the lawyers who specialise in employment law publish guidance and examples of Adverse Action cases and/or information about cases that have already been settled.
A quick
Google search will generate plenty of information. Here's one example that looks quite useful
Kemp Strang Lawyers - Adverse Action - the sleeping giant in the new era of Fair Work