You mean 2dice should have an investment scheme where we deposit funds to them and they pay us regular interest or dividend. I think you should not mix the gambling site with the investment site. Both of them are different in nature.
Personally i do not like investments sites. They are better suited to those who like to get passive income.
There was several gambling sites who offering investment option to the people and they too offering profit share on particular percentages which is usually monthly profit or annual profit so people can earn money instead of gambling through those sites so it's not impossible to combine between both of them and maybe this is can be good solution for gambling sites to increase their bankroll