Currently, all cryptography is only at the beginning of its formation. If you believe that crypto is our future, then you have no other way than to invest in crypto-currencies. Especially in such as bitcoin and ethereum. However, it will be more reasonable to add to your investment portfolio a few more large coins to reduce the risks.
Bitcoin and Ethereum should be part of any portfolio, not the fastest growing but less volatile. Most people are weak on diversification and focus either on small caps or established coins. Its way better to have a wide mix of coins like at least 10 or better 20 coins so if one coin drops by 50% you never loose more than a few percent.