All of us are bitcoin users from the start because it is the first cryptocurrency that existed. After so many years, altcoins are now included in the market but not that popular enough to surpass the value of bitcoin. Maybe if we use cryptocurrency in our investments and it can give a lot of profit, for sure these altcoins can bring profits also.
If you can invest on both bitcoin and altcoin, then that's a good decision. Bitcoin is volatile that sometimes its price is not moving in the market so you need to make another way to have another source of profit, and that's the opportunity for you to use potential altcoins. It will give you side profits although it is not that huge compared to the value of bitcoin but still it is a progress.
Maybe, they prioritize bitcoin so much that they don't see the importance of altcoins in the market.