That is why there is the best advice that we all know: "Only bet what you can afford" in gambling. If you can afford to bet 1,000 USD, that is the amount you can afford. But if you can only bet 1-10 USD. That's the amount you can afford. Each person must have a betting amount that he can afford, and it will be different from other people, so we don't need to make the same betting amount as other people. We have to adjust the amount of bets to the budget we have prepared to reduce the number of losses. Reducing the number of losses is very important because it is our money, and we do not have to spend it in gambling. We must always control the expenses we make in gambling. And in gambling, you have the opportunity to bet 1 USD, but it turns out you can win more than 20 USD, and that will only happen if your luck comes. But we can't expect luck to always come.
And gambling addicts place higher bets because they hope to win a lot of money, but that won't always happen every day. So they must be able to reduce their gambling addiction so they don't lose much money.
Of course, everyone should gamble as much as they can within their own budget. You should definitely not bet this amount using the excuse that someone else is betting high amounts. The reason why I specified the amount here and gave examples was that a person should gamble depending on their budget but this budget amount should not be consumed in one go, no matter what. So, if you have a budget of 1,000 USD for gambling you can spend 100 USD for each bet, this will not affect you much. However, if I have a budget of 100 USD, spending 100 USD at a time on bets will cause my entire budget to be zero in case of a possible loss. I hope that my example was more descriptive this time.
In addition, you example entails short term fun. Wagering all the budget at once, ends gambling for the day or week. But, if the person follows the step you mentioned he'll enjoy more time gambling and increase his chances of winning. A quality of frugal gambling. The mistake people make in gambling, is being sure of what would be the outcome of a game. When a player forgets he's gambling, he'll get sure of the game and wager huge amount of money. With his believe that he'll win, then the game turns negative in his eyes and fails. All the money goes. Greed is high and affects gamblers. We all think of the jackpot. That's why some players risk it all in, and go home sad. At last, players want to win big then stop gambling. Yet gambling changes the way we see it, the moment we engage into it. The advise we see here, like yours, it's valid, but doesn't change anything in gambling, for some. Because when they're on the machine, their thoughts don't remember all these frugal encouragements. It's like trusting your fighting technique in a fight. When the fight starts, those techniques disappear from the brain, we face it the way it is. Losing a lot in gambling can be frustrating. Nobody wants to be a loser. Hence most gamblers must keep gambling, even more than they can afford. Players take loan to play games. Do you think they don't see the slogan "gamble what you can afford" That I must win syndrome will overshadow whatever advise, technique or strategy they've got and lead them to gamble irresponsibly.
However, bouncing backward to Op's idea, it's a thing of choice. And every choice has its benefit and disadvantages. Although, to some extent playing a single game often times to master it can posses a minimal risk. Professional slot players cannot join a board game like Poker. They know its not what makes them happy. The losses could be detrimental, as they don't understand the game. So, if a person focuses in one kind of game for a long time, sooner or later they'll understand few things about the game. Depending on the person's sensitivity. And such practice can help the player to manage money. But, if a person can play more than 2 games very well, it's not bad. Or if a player wants to learn another kind of game, they can begin to try them out. So, there are different reasons to why gamblers wager on unique games. Maybe to enhance their horizon. The goal is to win. If a game doesn't favor a player, they can switch lane to another game. While trying both games, one can become better than the other. I've seen experts in Poker interested in slot games, and they do exceptionally great.