Does it make sense to buy anything else except BTC

All cryptocurrencies move in relation to BTC. Most have very low liquidity, and altcoins often experience larger percentage movements both upwards and downwards. Layer 2 blockchains are working to enhance Web3, while other high-cap altcoins are focusing on various use cases. I have compared the performance over the past year for all of them using a crypto calculator. Considering the gains, is it worth adding other coins that potentially introduce more risk?