Basically if a site has permantely zero house edge, I would steer clear. How are they making a profit?
It's acceptable for a site to have a promo where they have 0% house edge for a short while. However having it permantely it makes no sense.
Hence it might be a scam of some sort.
Theoretically, it is possible for a gambling site to profit from a 0% house edge gambling game. There are two reasons why, first is bet size limits and the house having more money than the player.
Imagine a situation, where a gambling does a martin gale system bets and the casino has a max bet of 1 BTC and lastly the gambler bets at 50% with 0.01BTC per bet. The scenario is that he cannot win against the house since there is still that chance that he will have a losing streak long enough to deplete his bankroll or reach the bet limit.
0.01
0.02
0.04
0.08
0.16
0.32
0.64
1.00
The gambler only needs to lose 8 times to reach the max. Even if you simulate this in a computer game with a lower starting bet or higher limits, it will result to a time that the gambler will have a long losing streak that would empty his bankroll.
The only problem is that the casino will not earn as much as the other casinos with house edge.