You are just trying to promote another site and trying to say negatively about bitsler. The monthly coupon or any type of coupon is based on the wager amount. If you wager 1000$ then you can't dream to receive 100$ or more monthly coupons. To receive a higher coupon you must have to wager a higher amount.
Gamblers must remember that casinos only earn a small amount of money out of the wagered amount and depending on the games they play this amount can vary and this affects the size of their bonus, if a gambler was playing a game with only a 2% house edge and they wagered 1000 the casino on average just earned 20 dollars, so when you think about it the casino cannot really afford to give a huge bonus to that player as they are barely profiting from them.