I know it isn't an investment, but in the last few years some "high risk" investment funds have appeared, and in them you can either lose it all or earn a lot of money.
Isn't this basically the same as gambling? Wouldn't it be faster to just deposit the amount in a casino? At least you'd be able to spend your earnings much sooner

Gambling is already considered as high risk investment bro when you don't let your money invest on that thing you can't earn profit gambling are created to earn bitcoin fast but there are risk that you will lost your bitcoin too that fast, Basically all people who earn is doing gamble activity.
No, not all gambling is created for us to earn profits and not all people who gambles are winning or earn in gambling. It is more on losing our money fast than we expected . Also not all people who earns comes from gambling activity it depends on people on what they do and where they invest to make some money.
But if we call that gambling is investment, So i think we should accept it, because gambling is a money game and we invest or use money in it, So it has clear mean that gambling is like a investment, than also if we use "High class investment", no doubt, it is right, because of risky wise.