You don't buy coins blindly because it is cheap so you don't get trap. Many projects are dead on arrival and so when you invest, you go down with it . You need proper research before investing on any project.
I agree in what you have said because not all coins in the market is worth to buy and invest. Even a coin is in a dip, you should always do some research and study the market movement of these coins. Don't waste your capital in many worthless coins instead invest wisely.