The people who have lot of money can be a good gambler because they won't get much life problem even if they lose money in gambling so when you want to gamble make yourself rich.
Sounds good but even he has a 'lot' of money. It's still limited, if that person won't be cautious and careful enough to maintain his standing and can't control himself, he can still become a bad gambler. That's the start of someone who's getting addicted with gambling for having a source. But there's also a bad side on it because of abundance, he can abuse himself. A criteria of a good gambler isn't all about the amount of money he has but on how good he is not just on how to gamble but also in controlling himself.