They'll probably trade in all major cryptos eventually.... I head they're adding LTC and NMC as well. Though I'm not really clear on why so many alternatives are even necessary...
Why would it need to profitable? for that matter - why should bitcoin be profitable? The whole idea is to replace government fiat, not to be a high risk venture so people will buy BTC and change them back to USD as soon as the price shoots. As I see it, the end goal is to have a bitcoin economy independent of any currencies.
I've seen several people talking about how BTC will be the "rich" money and LTC the "regular" money of the cryptocurrency system. Though I'm reallt not clear as to why anyone would think that, apart from "BTC was here first"... Is looking at the current exchange rate between these coins to the USD supposed to be some indication? it seems absurd if the endgame here is that BTC will not need to be exchanged for any fiat currency to be viable.