I personally think freebitco.in has a good referral system not only because we earn from referrals but also from their earnings as well.
All the referrals that stay active and keep betting on the site earns some satoshis and we get a cut from their winnings.
Also, if we hold more than 30k satoshis in our account then we get interest paid on it daily in our account.
Agree with this. That is what we can offer to our referrals if they want to earn some satoshi on that site while they leave their account and do not want to play gambling. Besides that, they can become investors of the FUN token and earn more FUN tokens.
I think the earnings on the referral system on each site will vary but those gambling sites will give their best to their members by offering a good referral bonus to them.