It is possible to make good profit from trading and your money is guaranteed that no third party can withdraw your funds but profits may be more or less and losses may also occur but you will not lose your entire money.
In casinos, there's no third party that will withdraw your fund as long as you won't share your account to anybody.
On the other hand play gambling where after placing a bet then if you lose then you lose the entire amount, and if you win then you can earn double money.
The same goes with trading, if you lose your trade then you also lose. And just as what you're saying with gambling, you can also gain double possible.