Time limit won't be effective because someone can bet a million dollar in single bet and lose all at once so instead of thinking that sites should stop the addiction.
I dont consider betting million dollars at one time as addiction, it is just you just have. lot of money which can make you bet that amount of money, addiction is something you can focus anymore on doing other things just because that thing is consuming a lot of your time and cannot make you think good anymore because of being addicted on which time limit might be useful in that case.
But it could be that betting millions of dollars is a gambling addiction, especially if we don't know the truth. But those who often bet with big money may not feel anything because it's normal for them. But not for those of us who never bet big money. Many things can cause gambling addiction, and it will be difficult to leave if we are already affected by it. And before gambling addiction came to us, it was better for us always to try to control ourselves and manage money to gamble.