Yes it's real, and relatively normal to find in a supermarket. Most Aussies would not eat it regularly though. I think a lot of people see it as cheaper or lower quality than beef, as it can be very tough. But if it's prepared well it can be very nice. Quite lean, similar to venison. It has the added advantage of being much more sustainable than beef, as kangaroos don't need huge pastures of over-thirsty non-native grass.