1\. International exposure. The fact that I don't watch Gaelic football or Lacrosse or whatever other awesome sports are probably played in Europe and around the globe is because I'm not exposed to it, never understood it, etc. League could gather an international audience through such a promotion in the US, however small it is, which will generate further income for the game.
2\. Rivalry. I would get into the Club Challenge if it were fair. The fact that one team is playing in it's home country, without having to travel a massive distance, is never going to produce a classic game. This competition would not only increase the rivalry between the ESL and the NRL, but also give more of a rivalry between England and Australia in sport, which I see no issue with.
3\. Incentive. We finished 3rd this year and didn't get rewarded for it whatsoever. We were essentially saved by Manly, who failed to pick a team capable of competing with the Dragons. As more teams opt for the bigger venues as home fields (alla the AFL), the competition would be a furhter incentive to finishing in the top 4.
Happy?