Most likely he will use it as long as it's hidden and no one knows about it but mostly as well he will be found out. But as soon as he found out, he will be in trouble unless he knows how to disappear before that even happen. Because of greed, most people don't always stop when they find a loophole in gambling, they mostly abused the bugs in order to gain more money at the end of the day greed will hunt them and they will gonna lose their money because of that, just like what we heard from the stories of others.
As long as he could continue to use it, he would still use it for his own benefit. And if it is no longer useful, he will likely sell it to someone else for more money. But the casino will check every system in the casino and immediately close the bug if there is one. The casino will also know if someone is trying to use it for its benefit and will either block the account or not process the withdrawal. But it's different if the casino holds a contest to find bugs, it will make people compete to find the bug and report it to the casino to get the prize.
They will but that doesn't usually happen in reality as often times, most gamblers would say that why would they help the casino find it when they have their own stuffs to do it and apart from that, they will not because the prize will not be as big if they will take advantage of the bug themselves. You know, those kind of mindset that do it now without trying to look for the consequences down the road because the important thing is to make money.
I quite agree with you input though, But then , i think there are no mention of amounts a casino is willing to pay the bug hunters, i mean that, casinos usually do not mention the amount of money they are willing to pay anyone who finds a bug and reports it, so, there is clearly no way a hunter should think that the price is too small, then proceed to taking advantage of the bug by exploiting it, so for me personally, anyone who finds a bug in a casino's system and did not report it, but rather went on to exploit it, with the excuse that the bounty for discovering the bug is always too small if they do not exploit it first, that simply means such a person has evil intentions in the first place. it is highly possible that as the exploit the bug, if they casino does not find out, they will keep doing it just to enrich their pocket, i personally will always advice against such.