Roobet has always mentioned how they have a higher house edge, however they have also said that they make up for it by having the biggest giveaways and promotions, basically returns to players as well.
What this achieves is that if you win nothing in the end, you lose more here than any other place, so if you think you are unlucky and will win nothing you should probably pick somewhere else but they will have house edge too (even if lower) which you will lose anyway.
However if you feel lucky, when that many people pay a higher house edge, the giveaways makes sure the winners of those promotions are not in negative, even if house edge is bigger, the giveaways makes sure that you earn money instead, so winners gets a positive return on average and losers have bigger loss on average. It all depends if you think you will get anything or not.
I do not think that having too many promotions is the reason why they are good, I think the way they do the promotions are the difference. For example there is one famous casino that I shall not name, they are amazing in promotion numbers, they have been doing promotions for almost 8 years now total and 3 years with the new website and I think they are a good website too but they have done thousands of promotions so far, yet none of them got this much attention. Why? Because none of the promotions were this interesting.
Roobet has promotions and yes the number is big but that is not the important part, every single promotion they do is amazing and calls out for people, you see it and you want to participate in it, which is the root cause of why roobet has been so loved.