Nutshell:

Due to the ability to trade in-game items (weapons, primarily) in first-person shooter (FPS) games, Australian politician Nick Xenophon is calling for titles like Counter-Strike: Global Offensive and Dota2 to be classified as gambling.

More:

According to the Sydney Morning Herald, the weapons in the game are assigned a value according to rarity and it’s this that causes the (potential) problem. Assigning a real-world value to something that appears by chance is already not allowed in Japan.

There are also a whole host of other associated issues here, like the rise of eSports in general and the associated gambling that goes on around those events.

For now, at least, it seems unlikely that there will be enough political appetite to reclassify Dota2 and Counter-Strike as gambling, but stranger things have happened.