Hello,
i cannot understand how such a business would be profitable for you.
You are taking the role of a soft bookie,you will be giving free money to your bettors.
Even if your players using only your coin for betting(assuming the coin is trade able).
In the long run you ll loose money.
Most new platforms do so because they want to advertise their platforms, giving out native coins to be used on the platform is a way of giving back to the society to build clients base since the coin can only be used to place bets on the same platforms it's most time hardly get listed on exchange to make the coin revolve around the platform. It a good strategy.