The below is my take on HYIPs.
"All HYIP is a scam and never invest a single penny in HYIPs"
Be it in a smart contract or not, none of the HYIPs can be trusted, even for a moment! That technical mumbo jumbo looks great on theory but when a HYIP promises around 20% of profit within few days, it's an obvious scam!
No real world business can generate a steady stream of such revenue to pay back its investors! So it's a cash rolling business at it's core! Not to be trusted and not to be recommended!
Thanks for the opinion. Do you like casinos? And to sports betting? And to the slot machines?
There you promise much more instant income!