I think that if you will send your referral link to everyone - you can`t reach some nice profit if you haven`t some resource(website with reviews for example) with lots of new visitors. I don`t think that the big gamblers often register with such links. But if you have friends, that wants to gamble but don`t know how to start - it is possible way to get several $ for advices.
There must be a strategy on this one and it's not just all about sending your referral link to everybody but making such story that will enticed your target referrals. But of course, be truthful to what you're going to write or make.
Those big gamblers don't want to be under by someone like a referral because they don't want others to make money out of their deposits and money.
But if you've got one and it's an active gambler then you're in luck on having one.