I think we really need Altcoin.
If there is only Bitcoin in the Cryptocurrency market, Cryptocurrency will not develop.
Meanwhile, Bitcoin has a very high price value and not everyone likes Bitcoin.
There are many people who tend to like altcoins because the value of the price is still low and has the potential to rise in price in the future.
In some aspect of trading yes we need altcoins to be able to get yourself involve here in crypto world or market. Though it would be better to own bitcoin or Ethereum since they are the crypto coin that established their technology fully but since it is too much to afford that's why altcoin is important.