I have used the vouchers at:
Sofitel Wentworth Sydney
Sofitel Melbourne on Collins
Most properties in Queensland - and definitely Sofitel Brisbane - do not participate in A-Club. At both the Sydney and Melbourne hotels above all A-club benefits are honoured, and the vouchers are accepted as cash would be for all services under all conditions (so long as you are staying at the hotel).
I burned EU400 at the Sofitel on Collins 3 weeks ago against a total bill of AU$2,400 or so.