There are lots of scam in the crypto space so it is very important to be very careful before putting money in any projects. I see a lot of projects and their developers give them hype to get investors, but in the end most of them will fail and people will lose their money, I think that the best thing is to research any one of them that you want to buy to find out if they are good projects or scams. That is why I love Bitcoin more than every other crypto coins in the cryptocurrency market, it is the most reputable among all of them to do investment. Some top rated altcoins are also good for investors to buy, they are reputable like Bitcoin. Ponzi schemes are very dangerous to invest money in them, they can shut down with people's money at anytime.