New projects are not harmful if they have something to show up! If you recheck, you will realize last year we got some extraordinary new projects like Harmony, Elrond, Matic, Sero,Perlin, and so on, and this year we are getting more potential new coins. Now you see the Defi idea is ruling! So, new projects are not that bad, and you just have to pick the better one!
Yes, I completely do agree with you, It is not necessary that a new project is a scam or it is not useful. In fact, new projects with great ideas and potential can make itself a secure place in the crypto market. People are getting tired of those project which has been based on the same idea or hasn't had the potential to grow a lot more.
In general, new projects can help you to make a profit if you have a reasonable investment strategy because the trend of people seems to be believing in more potential investment options. In fact, any investment is risky and can make you lose at any time, but I believe that if you have the knowledge and have been involved in this market for a long time, you will know what to do next.