How so? Is it just pricing weirdness?
Here it works out to be about a AU$5 saving compared to physical (most games can be found for AU$69 here physical), or up to AU$45 compared to digital (some games are AU$90, most are AU$80, so a typical saving for most cases is AU$25). You also get about $6 worth of golf coins too, which you could add to your saving. So here it's a great deal if you want to go digital anyway (which I typically do for casual MP games like Mario Kart), but not that great a deal if you prefer physical. If you factor in the benefits of physical (resale value, preservation, sharing), you could argue the vouchers are a worse deal, but that's only if you love the benefits of physical.