I had this same offer on two accounts except 1,500pts for a $50 Liquorland spend (plus shop at coles same day).
Used it twice on each account with no issues. Was in one transaction each time though.
I'm considering trying to use it again. Maybe beers for christmas day... Still I'm just collecting FB points with no purpose
The multiple transactions was because the displayed pricing of wine at the local liquorland doesn't match the computer.