If you want greater returns, then you need to go for HYIPs and other high-risk investments such as Bitcoin.
You can't seriously put HYIP's and Bitcoin in the same category of high risk investment options. Bitcoin offers a long term growth opportunity, which at the same time can function as currency, store of value, hedge, etc. HYIP's are nothing more than pure scams. In that regard, I am quite surprised that you advice people to put their hard earned money into obvious scams. It's a shame.
Not all the HYIPs are scams. And I am not advocating anyone to put their hard earned money in to the HYIPs. I have always made my stand clear. IMO, no more than 10% to 20% of the net worth should be allocated to the high-risk investments. And regarding the HYIPs, you need to carefully study them, to determine whether there is an adequate risk of losing your investment.