Is there also a no-depositbonus? To try the site before doing a deposit?
Bitcoin sites don't usually offer no deposit bonuses. Also they offer bonuses on almost every deposit you make, even after your first 4 deposits you get bonuses every Monday and Wednesday.
Most all new bitcoin casinos offer no deposit bonus/free spins. It is as their first promotion to introduce the site so people may try it without any risks of losing money. Deposit bonuses is also a common promotion but it wont attract many players because of the wagering requirements.