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.
It is nice to spend more time researching than spend more time investing. When you have the right information, every other things will fall in place. The Idea of portfolio diversification is not as easy as it is being said. While Bitcoin investment might not require some tedious kind of research, investment in altcoins requires such a research.
That says volume of why many people fail in the altcoins investment because they do not have the skills or concentration to understand how the cryptocurrency market works as regards altcoins.