Maybe best site is not the right or appropriate term even with that famous gambling platfrom you mentioned since best means has higher chance of getting more and stable profits in a long run. If you will look in their calculation of profits when you invest in their bankroll (if ever there is a present calculation on the site) you will noticed that profits are not that interesting if we cared for a long run profit. Yes house always win but if it's really productive then why we can't see others putting seriousness in that type of method? Meaning it's not that appealing to anybody.

Others can look into risk on investing on gambling sites bankroll and can consider that as a side income although don't expect too much profit even you put some big capital out of it.