As long as you are doing your research, alt coins may provide decent to huge amount of profits.
If there's a good usage for a certain project, collecting those assets will be good for your long-term investment. It's been
proven by those who bought ETH and BNB, they are all enjoyed from what the success these two coins provide.
But, it's also better to have Bitcoin the most, in terms of long-term holding Bitcoin is still the best option, in my own opinion,
as others may have their own choice of assets to invest.
If a coin has a good use case, there will always be people that will buy it because they can use that coin on a certain service. That makes that coin increase over time. That is why it is one of the famous advises for the investors but we cannot deny that until now there are still investors that are hard headed and will not follow an advice like that because they still invest on shitcoin, meme coins, or coins with no real world usage.
That's why they lose. Eth and bnb can be a perfect example for a coins with good use case but there are also top coins which have the same purpose like them but I wonder why people still prefer eth and bnb? though yeah we cant disregard btc, this should be the base of our portfolio.