There are cryptocurrencies that are scam but not all of them. Most of them actually are legit and can be trusted by people. Some of them are already tried and tested by most of people. We can enumerate some such as bitcoin, ethereum, ripple, bitcoin cash, litecoin, cardano, and others (coincapmarket.com). You can look at their statistics if you are looking for a great cryptocurrency. It is not true that all of them are just scam.