Oh wow! Interesting information! I don't really play there, so I wasn't aware of their VIP System. Yeah, You are correct that most casinos have a fixed amount to reach VIP levels and a fixed level-up bonus. Interestingly, Duelbits share 12.5% of their house edge. I am curious how it works. ~
You may lose more amount by wagering the same amount in the higher HE game than the lower HE game. Although it depends on luck, but it is effective in the long run. Still, Duelbits rank up bonus system is far better than other casino as it is connected with the house edge of the game. There is a probability of losing $66 for every $1k wager on the 6.6% HE game. And you will lose $10 for every $1k wager on the 1% HE game.
Quoted things belong to every casino. You will lose more if you play the Higher House Edge game, no matter which casino you play. Roulette games House Edge is 6.66% in Duelbits. But, You can find other roulette games with a lower house edge, which could be as lowest as 2.70% (European Roulette). But, the thing is, Other casinos are not going to pay 12.5% of the 2.70%. Here is the difference between Duelbits and other casinos and this is where Duelbits far more better than other casinos.