in wagering contest: you deposit money(no bonus and play, wager more than others - you win.
in BTC deposit bonus: you deposit, you get bonus and play, if you met requirement x91 - you take all your money from the balance. If couldn't you can withdraw your deposit(if you didn't spend it). So at the end in this case player don't risk and spend money.
Okay if this is not a wagering contest then it may not increase your traffic because as I know most site will offer this kind of promotion to attract more people here. But you guys made a deposit bonus with of course really huge of wagering requirement so I do not think this will get to the players as well. Other casinos will offer lower than 91x of your deposit. May be you should adjust it to get players first
Are you comparing the wagering requirement with non-dice sites deposit bonus which has around 35-50x wagering requirement but players will only able to wager it on slot games? If no, mind to give me an example of a dice site that offering deposit bonus with lower wagering requirement than this site as I cant even find other dice sites offering deposit bonus (at least most popular dice sites does not offer deposit bonus).