I totally agree with your opinion, because the best investment in cryptocurrency is Bitcoin, therefore investing in Bitcoin for the long term is definitely safer than altcoin, because the price of Bitcoin will definitely continue to increase and give us a big profits in the future, so there's no need to be afraid to invest in Bitcoin for the long term, because Bitcoin is the king of cryptocurrency, so Bitcoin is the determinant of the crypto market price.
You are right that by the way there are many coins in the crypto currency market, but Bitcoin is the single most trusted crypto currency. The first reason is that Bitcoin is the leading crypto currency, and the entire market follows Bitcoin. Fluctuations in the price of Bitcoin lead to fluctuations in the entire market. Well, in every business there are risks, but in the crypto currency market we consider our investment in Bitcoin safer than altcoin. Of course, it is a good choice for long-term investment, but this does not mean that there are no good and excellent projects in Altcoin. If one invests in good and solid projects after proper information and research, good profits can be obtained from there.
Even now there are very good coins in altcoin that can be trusted, and have the potential to give good profits in the future. So in my opinion one should definitely invest in Bitcoin, but also invest in altcoin. Our capital is safer in Bitcoin, but the rate of return is lower than Altcoins. Altcoins can be risky, but the returns are likely to be much higher than Bitcoin. So in my opinion it would not be a good decision to completely ignore altcoins.