Unlike before when you go to casino you just bring such amount and after you lose you can go and stop and leave the house, with online access you can top up whenever you and the risk of getting aggressive can lead you to lose everything in your savings.
This is what's happening to most of us. We're there to gamble in the physical casinos but then, if we've got some cash cards or savings card, we tend to use it as well and withdraw money from the ATM and still use those money for us to keep going. It's the same as online but it's more of a hassle when doing it plainly with cash and physical casinos.