Keeping money in the gambling site was a stpid idea but many people are still doing it right now. I meant earning more money through refferal was good but it also depends on how active our referral is. So many time keeping our money in the gambling site be result in a lose once the site will be gone or disappeared due to the hack.,
If they have succeeded in making more money through their referrals, they should immediately withdraw their money. That will prevent bad things that might happen to our account. We also don't know whether there is a hack on each user's gambling account or whether their gambling account will remain safe. The important thing is that we have to prevent it before something bad happens.
Saving money on gambling sites is just to prepare some money for gambling. Don't keep too much money in a gambling account because you don't know what will happen. It's better to prevent it than regret it later.
And keeping only the money we can afford also prevents us from betting more than we can afford.