Cryptocurrencies are too much correlated to Bitcoin. If he plunges then all altcoins will follow the same path or even worse. For me, buying only Bitcoin is the best thing to do at this moment.
On the link below you have some plotted data:
https://cointimes.com.br/investment-diversification-in-cryptos-bad-idea/For example:
Correlation between Ethereum and Bitcoin is 0.82 which means a very strong correlation. In 2017 the same correlation was 0.41. For me, if you're diversifying in two types of assets that have the same correlation you're doing it wrong.
What do you think about it?
Yes but emerging ICOs see a lot of growth, if you have picked the right ones ofcourse. If you find a coin that you are sure to invest in, correlation does not matter because thats cyclical. In the end a strong altcoin would grow in the long run. Also if you have all your money in bitcoin, you will not be able to earn returns on a short term basis. Smart diversification is always a good idea.