If you ask me I will say only buy Bitcoin but I see why latecomers are attracted elsewhere, there are other cryptocurrencies with unique features & potential for large growth. Diversification is key for some people, It is advisable to research & understand the potential of different cryptocurrencies considering factors such as technology, adoption & market trends. Each cryptocurrency offers different opportunities & risks so a balanced investment strategy that includes a mix of cryptocurrencies may be more beneficial for some in the long run.
Diversification is definitely a good thing but the problem in my opinion with that is that not all altcoins even those with promising technology and other stuff, you're still risking a lot of your money in diversifying in hopes that you can hit a lot of altcoins and get more profit when you can just buy bitcoin and hodl, it's more a better option that diverse number of crypto because with bitcoin, you're guaranteed to make a profit if you're patient unlike altcoins that are 90% likely not to go up after one peak in prices.
I somehow disagree with your comment.
I think the key point in making an investment is being smart- meaning, knowing which altcoin to invest in. I agree, there are lots of altcoins that offer promising technology and innovation but only a few are liquid on the market. While I do recommend that a person should at least invest in BTC, I still think that considering the top 5 altcoins for diversifying your portfolio can be profitable in a few years.
At the end of the day, it is all about knowing which altcoin to invest and when to convert them to cash as soon as they reached a price that can profit the certain investor.