4% annual interest for a risky investment, for me, I think it's not worth it. It's more safer if you'll just deposit your money in a bank through time deposit, I think you'll get that annual interest or even more, depending on what bank you are investing.
I agree with you. Better to deposit in a bank that we can be sure to get the interest than to use it for a risky investment. By investing in the bank, we don't have to feel confused or heart attack because the bank will have a fixed calculation about the interest in some period, so people don't have to calculate or to guess how much money they will get.
But if he still wants to try with gambling site investment, let him continue to invest, and if he can continue to tell us what the progress is, we will know that gambling site investment will have potential or not. Perhaps, we need to prepare ourselves before we place the investment in the gambling site and don't use too much money to invest in the risky investment.