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.
I'm a newcomer and I share old timers believes, just like yours, that bitcoin remains the crypto coin that I can put my money in and go to sleep. It has proven it's worth as the pacesetter in the crypto market, it dictates the pace that others thread. Altcoins were painted like plagues to me before now, I still have a little of that phobia till today about buying them, but with my increased knowledge, I know that it's not all altcoins that are potential "shitcoins". I look forward to buying some top altcoins now, to cash in with my bitcoin, because I know that bitcoin bull run will make them to be profitable too. New projects can be more profitable but it's not for me, I like to minimize my loses.