I had a friend like that, he made insane amount of money from trading, zero emotions at all when dealing with millions of dollars that can be gone in a second, apparently that helps.
Trading is not easy and a bigger capital you are using for trading, a more pressure you have as well as bigger effects from emotion you have to cope with. It's not easy to repeat success from trading with small capital to trading with like x10 or x100 to x1000 that small capital.
When you are trading with very big capital, you don't chase for x2, x10 or x100 from it, you only need small percent of profit which is enough. You will prioritize safety and only open positions if you see good chance to get profit but it still has pressure. Big capital, big risk to lose big when you fail.
When gambling though, if you have no emotions then there is no need to gamble, because it's all about getting emotions back.
Gambling for fun is different than gambling for rich and do it irresponsible.
Yeah honestly you can always adjust the amount of transaction in the Gambling but in the trading world its entirely different dram. Somehow there is big role of the psychology while playing gambling games and investing money in trading. You see if you read the last sentence again then games and investment are the prime target words that are role playing here. Games, is lot easier or fun way to portray it and makes it look like easy environment to put your money. On the other hand trading is all about deep study, continuous watch on the market, complicated decisions and much more. So yeah it might be that gambling could feel way safer somehow if you control the emotional part.