It's simple. You invest $1000. Coin goes to $0, you loose 1000 usd but if it does 5x, you have +4000 usd profit. The risk and reward ratio must be good if you want to put money in something.
A coin that can go to zero is avoidable. You choose the best coins and you're unlikely to get into that price and lose your investment. Although there's really no assurance for your gains but with the best coins, you have a better deal with them rather than choosing those "gem" coins that can potentially lose your money. It's a real story that the more you're craving for higher profits and being ambitious for such coins, you'll taking more risk.