They say investing to gambling sites is much safer than doing trading. But if you really want to have control on what you will earn at the end of the day better do trading than investing to casinos.
"Trading" is a zero-sum game (atually worse because of fees), so it's very unlikely you have a system that makes you more than about the 50% annual returns that I estimate investing in Just Dice gives you.
Casino returns are quite stable and predictable. Especially in the case of Just Dice, because most of the profits (nearly 90%) come from staking, and the amount of staked coins is about the same every day (
https://just-dice.com/misc/wagered.txt).
It depends on how good you are at trading and he patient you are. Most people come in making big investments then losing it because they silly and they never thought it out properly. Rather make lots of small investments and secure profits in then and build your way up. Never use a large amount of your total to invest that is a mistake.