I dont know whether someone has seen this or invested in this but is this for real??
Depends on the ethical point of view
In my opinion these sites should not exist because they are created by thieves.
But there are a lot of people who look at these sites as a game and if in case these people are stolen they just look like normal.
Like a game where you have both a winner and a loser.
Of course people invest in these ponzi sites, if nobody invested in these sites ponzi you think someone would waste time creating a double script?
Hyip and double sites have their own niche market.
People invest money in this crappy site, unfortunately.