I can agree that the referral system is a serious problem to the casino due to multiply accounts and to situations when the referrer just withdraw his referral bonus. Possible, that it will change soon, at least this system needs some restrictions.
And the bonus system is the instrument to promote the casino. For the gamblers it gives a chance to test the casino without spending money. It brings much more profit to the casino when cheaters can get i think.
Well, there is no denying that referral systems make many people excited and start looking for many more to see if they can earn some more money, and some like it and have fun doing all that process of calling their friends, telling them that they support them to register and all those things that are done, but I think that currently people are a little reluctant to do so, they think that they will put them in a ponzio system or something and that they do not want to get chipped by those things, however it's a good strategy, and also the casino gains more fame, so I don't see it as bad, just like the bonuses I see it as a system to attract more people, but when they realize the terms and conditions to withdraw, that's it when they begin to dislike and become disappointed.
This system helps to everybody - casino gets new gamblers, referrer gets some profit(sometimes big enough). The only problem is cheaters - this is what the security service has to deal with.