Bitcoin is the best among cryptocurrencies, and all altcoin markets follow this Bitcoin. But altcoins are just useless, their future is not good, people just try to invest and invest with little money to get the most profit. And these attempts mostly fail, sometimes some coins are pumped and some people get benefits from it and the rest face losses.
Because most altcoins are destroyed from the market, but Bitcoin is the best in all aspects. So if you want to invest, choose only Bitcoin.
Most alt coins are pump and dump,they fall more than they increase but there's good altcoins to invest but safe to invest with your discretionary income.
When it comes to performance, bitcoin has no comparisons in the cryptocurrency market. Bitcoin is more trusted to invest due to its performance. Like bitcoin, altcoins are also good for long term investment. They are not entirely useless as they are some performing altcoins where you can invest. You should carry personal research before investing in altcoins to avoid invest in a fake coins.