I believe the OP talks about Edgless, an edgeless casino project on Ethereum. They had their ICO back in March and have been developing since than. Even with %0 Edge casino still can earn through the profits. Read the Edgeless whitepaper. It's pretty mathematical actually.
This is from the Edgeless FAQ:
There are several ways how Edgeless Casino can be profitable. Edgeless Casino provides games which depend on LUCK+SKILL and Sports Betting.
The first two games provided will be Blackjack and Video Poker. Both games are played with a combination of LUCK and SKILL. That means players make choices and either play well or poorly. To give an example of such a situation:
Blackjack:
House has a 6 card.
The player has 16.
The player wants to collect at least 17 and hits for one more card. - BAD MISTAKE.
The player just made a huge error, because, 12+ against 6 ALWAYS STAYS. (according to Blackjack basic strategy)
An average player does not play ‘the perfect game’ therefore, in the long run the casino makes a profit from his mistakes.
An analogy can be taken from poker. A new player is playing against a Pro. Both have equal probability conditions - 50% vs. 50%. However, the Pro player makes better choices and the new player makes bad decisions, and in the long run, the Pro wins.
Look at this EXTENSIVE RESEARCH from players’ mistakes in Blackjack - on average they give away an 0.83% edge to the casino. https://wizardofodds.com/image/ask-the-wizard/how-poor-are-bj-players.pdf
And that's exactly what the casino will earn - 0.83% which is the same as playing dice with an 0.83% house edge
The second stream of profit comes from sports betting. Sports Betting connects bettors against each other, charging vig / juice / rake from each side for their bets. In this area, the casino will earn 4% from all money wagered. An analogy can again be taken from poker. Imagine two players are betting 10$ against each other and the rake is 1%. So, they are actually betting 9.90$ and winner gets 19.80$.
More information on how sports betting is making money:
http://www.biasharainsight.com/2016/01/how-do-sport-betting-sites-make-money/
To sum up - the first stream of profits is from games of luck+skill. The second stream of profits is from Edgeless casino with 0% edge games and is a very strong marketing channel for attracting players to Edgeless Casino. Gamblers can enjoy fair betting conditions, and a good percentage of visitors will do Sports Betting which generates 4% returns to the Casino.
The concept has not literally come out of the blue - discussions on zero edge casinos are already occurring in the community.
https://www.bitedge.co/blog/0-house-edge-provably-fair-and-trustless-gambling/
https://www.reddit.com/r/BitcoinGambling/comments/36z3
wi/which_is_the_lowest_house_edge_fair_bitcoin_casino/