People want to become profitable from cryptocurrency. Some people want secure their fund cause it needs to take higher risk for higher gain that's why btc is good to be hold. Might be give you Small profit but safe. And altcoins are risky. altcoins will give you much profit. A multiple time higher than bitcoin and that's why people jump to altcoin investment but they should keep it in mind that altcoins can trun into shitcoin anytime. So make diversification, buy both btc and good altcoins for best deal
If you want to invest in cryptocurrency, you should definitely choose Bitcoin first. You can invest in Bitcoin as well as Altcoins. But try to invest mostly in bitcoins, invest a small portion in altcoins. It's not that investing in bitcoins can't earn high profits, if you can patiently hold bitcoins for a long time, you can definitely earn huge profits. Investing in altcoins is risky, holding altcoins for a long time becomes risky. Invest in Bitcoin as well as invest in the top altcoins on the market.
Both bitcoin and altcoin has its own potential risk and potential profit so we should know which one to invest depending on our own investment budget and plan. I can say that bitcoin has less risk than altcoin but bitcoin requires us to have enough starting budget in order to make significant profit while altcoin has bigger risk but it may give us bigger profit with lower amount to invest. In other fact, investing in altcoin needs more researches and we may confuse on which altcoins to invest so it can be time consuming. In my opinion, if we can invest on both will be better than if we have to chose one of them.