That is kind of the whole point of investing into a casino and that is why many people do it, because we do not have savings account in bitcoin world.
Hmm,,, that is a strange reason to want to invest. Savings account for me should not exist, that is the role of the bank, I want to have crypto I should keep it on my own and not expect "free money" as interest. I invest in bankrolls and I know the risk that comes with it. I know very well I can lose it if luck is not on my side.
If you do not want to consider it that way, it is totally fine, nobody realy forces you to consider it as savings account or stock market or anything like that.
However, do not forget that the idea of bitcoin started as "be your own bank" and when you are investing it to another company you are no longer in charge of your own money. That company could do anything with your money and you have nothing you can do about it but try to withdraw and if a place gets hacked you can't even withdraw.
This in return means that you are no longer in charge of your money, which is just like banks, where you put your money into bank and get free money in return of letting them use your money instead of yourself. So when you invest your money to a bankroll in a casino it is "a bit" like savings account at least isn't it?