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No that's a bad idea. If the reason for gambling is to make money online then trying all the game would make the gambler lose all his money in the process of trying the games. We all know so many gambling games are in Casinos, at least there are more than 22 casinos games. I dont think any gambling would choose to gamble on all of these game before choosing his preferred one.
In my opinion i think he should go with the game he is familiar with. Like the one he has more clue about. For me i know a lot about sports so when i started gambling i tried sports gambling before moving into racing.
No one was born learned and familiar with all the games around. So how do you get familiar with some games? You decide to try them and you play them... The bad idea would be to try them with some high stakes, when you are doing something for the first time you need to take it easy & slow. That usually means checking the rules, playing with minimal bets, and learning more about the game while you play it.