This is a deal for those who would use them. Best suited to businesses who still use snail mail, or those who still send Christmas cards.
Basically you can use any photo/design (subject to decency/copyright rules) and make real Aus Post stamps out of it. I use it for my business to send Christmas cards each year.
Normally these are $26 for a sheet of 20 x 65c stamps, but with this deal it becomes $16 per sheet of 20 stamps, or 80c per stamp. Of course you're spending more than face value, but the branding opportunity is never cheaper than this.
($5 shipping)