For the sake of argument, let's compare Kwari to a game like Dungeon Runners. What makes Dungeon Runners RMT compliant is that you can use good old-fashioned American greenbacks to attain items in-game that would either take a tremendous amount of effort to gather, or aren't even attainable with the base game at all. It's a purchase as much as anything, and the transfer of funds is limited in one direction by its design. This sort of business model is meant to subsidize a game that is otherwise free for players.
On the other hand, there is a game like World of Warcraft, where RMT is strictly prohibited. Players pay up-front for the privilege of having access to all the content. You can't pay a higher monthly fee to see better content or get access to better gear. Players are all more or less equally capable. That is, unless they take a trip to the gold seller. Where gold sellers come in is in helping players access the content they want more quickly by selling them in-game currency for real-life cash. Gold purchased in this context is used to enhance the gameplay experience of the player. Again, the transfer of funds in this case is linear. Players are paying for an in-game service. The value of this service for the player is in saving time that would be better spent experiencing the content.
Neither of these models is really comparable to Kwari. They both involve a linear transition of funds; the player pays somebody to attain in-game status and wealth. Perhaps the closest corollary then to Kwari is the gameplay experience of a gold farmer. The farmer puts in a monthly investment for a game like WoW, and gains in-game assets that have a real dollar value to somebody else. While he has to put money into the game at the beginning of the month, he's going to make a net profit through the sale of these in-game assets. And yet, the gold farmer's whole racket is dependent on the fact that most Western players don't view in-game gold as a real life asset. Moreover, there is no element of chance. Outside of the monthly fee, there is no chance that he will "lose" the game and forfeit his initial investment. He is extracting real wealth from the game.
So what of it? Would it really be possible to develop a game where the economy is driven by the power of the all-mighty dollar? My suspicion is that it's simply not possible, at least not in the immediate future. In order for an MMO to work on the same model as Kwari, there have to be winners and there have to be losers. MMOs are (for the most part) driven by the spirit of cooperation; players come together to fight foes because they all stand to benefit. There is no loser in the traditional MMO experience, giant dragon or slumbering old world god notwithstanding.
As with other forms of gambling, Kwari is a game bankrolled by the losers. It's a zero-sum game, where money is extracted by the losers and fed to the winners, with a healthy chunk skimmed off the top for the developer, of course. A game where every battle and every NPC interaction stood to rob the player of real wealth would be a dark place indeed. Griefing would cease being the realm of petty asshattery, and would enter the "serious business" realm of virtual theft.
Greater minds than mine have pondered the issue of RMT at length, but even those luminaries probably underestimate the devious ingenuity of developers like Kwari Limited at trying to squeeze an even bigger chunk of change from the pockets of gamers. It'll be interesting to track Kwari's progress and see whether any of those business ideas bleed into the MMO space.