It is better to have many altcoins in order to have more money to trade and earned a lot. Having a lot of altcoins in your hands will have a greater chance to earn big amount.
choosing only 1 altcoin has a big advantage and risk, I will buy lots of special proportions of altcoins, and I will buy it with several conditions, must have transaction volume above 500 BTC per day and listing pass several major exchangers such as binance, bittrex, bitfinex