There's a another, more complete article on it here:
The instant deposit / instant withdrawal / never keep money in your account and deposit 6 times a day
business model of Bitcoin is definitely a threat to "real money" or "fiat" casinos. But it's also worth noting that acquiring Bitcoins is still hard enough that my site (a casino not mentioned in those articles) deal with dozens of people a day trying to grind out 0.1 BTC, or the equivalent of $1.70, just to possess a small amount of coin. Right now, while it's possible to do an end-run around US law this way, it's still just not a viable option for most non-technical players.
The casino that netted over $500k also isn't a threat. It's not really what you could call a casino, it's more of a numbers game based on the long string of the transaction ID that's generated whenever you send Bitcoins to someone else. This is a random number, so the casino uses it to decide if you win or lose a bet. It's super-simple: Basically you send them a coin and based on that random number you either get back almost-double or you get back nothing.
The other casino mentioned is an actual blackjack/roulette/craps/VP casino that is open to the US, all HTML5 and original software and provably fair in a way where you can type in your own scrambler code to randomize the RNG on each hand (which works well as long as the games aren't multiplayer). It's not bad, and I even play there a little. From the Forbes article, it sounds like they brought in $72k this year or so, which is well more than us since we're not open to the States, but still not what you'd consider a threat. They're pushing their max limits, hard, up to around $250 per hand in blackjack while our max has stayed at $25. Even considering the fact that their overhead is probably like ours -- only about $400 a month, it's still peanuts. But it may get somewhere in the next year or two if the federal government and the states don't shut it down hard between now and then.