Investing in a promising ICO project will bring you a lot of money, but investing in a scam may make you lose all your money. So whether the ICO is worth it depends on whether you have chosen the right ICO project.
You will earn higher returns of investment if you do know the ICOs that you're investing because not all of them will succeed, hit coin exchanges and listed on coinmarketcap.com.
But in my personal reasons, I do invest only on new altcoins on crypto exchanges and more especially when they are being listed on coinmarketcap.com