So taking up those initial rewards helps us gamble for a while on that new gambling site. With that experience I make up my mind whether to continue or not.
Most of the times I tend to end up playing in my favorite sites alone but I have found these sites the same way.
Basically, I play on the gambling site until it is providing me a good experience of gambling.
Maybe, at the start, you can try their bonuses or rewards but using small deposit money only.
As they have no credibility yet, you have no idea if they will pay if someone wins big.
But to give the benefit of the doubt, we should not over criticize new casinos.
Everyone here starts from that stage, and as years passed, that's when they can prove their worthiness as a casino.