This is the same with cryptocurrencies in general
People had been "diversifying" by pouring their hard-earned cash into all kinds of fraudulent schemes (like shitcoins, shittokens, rogue casinos, and whatnot). And when everything started to crash at the end of the day, they were bitterly surprised by the results of their "diversification"
It turns out that when you diversify recklessly and thoughtlessly, for example, by investing in every new casino on the block, you are not so much increasing the odds of making more money as essentially multiplying your chances for losing most of your investments
Diversifying your investment is just part of the strategy to minimize the risk, it is necessary that you choose the right project based on your opinion and this one should be a well research project whatever it is. In gambling, it's easy to find a good and reputable gambling site but there's always a risk since you are putting your money without insurance, unlike depositing in banks where you can recover your money in case of bankruptcy
It is a bit different in gambling
For example, you can find a decent coin which you think is way undervalued (that may well be the case). Then you grab your money and invest dough without much ado. So it all comes down to finding a coin worthy of investment, right? Right, but this is not the case with bankroll investments. It is not enough to find a decent casino to invest in. That casino should also offer this option in the first place
And here's the catch. Decent and trustworthy casinos typically don't allow outside investments. So you are kinda stuck with not well-established gambling institutions often frantically searching for more money. That makes your bankroll investments risky by definition. And what adds insult to injury is that once a casino gains financial muscle to move on by itself, it is more than likely they are going to disallow such investments at all