Just like the way most of us want to invest and cash out immediately lol. But then, if we you are in a big project and you see a glaring future about it, it's good to invest and let it grow, not only short and quick investment only.
Few coins are cool for very long term investment, I agree with you. But there is nothing wrong with making quick gains on some trade setups, speaking from the angle of a price action trader. Sometimes I see highly profitable setups with good R:R ratio and swing trade them for short term purpose. This doesn't mean I don't keep some coins for very long term.
If you can do both then there is nothing wrong with that, it is just that in my experience people tend to specialize in one particular field, there are those that trade for the short term and those that trade for the long term and it is odd to see a person that can do both successfully, but if you can then more power to you as you can get the best of both worlds, you can invest in very good coins like bitcoin or ethereum for the long term and get profits in the short term with many other coins that are more volatile and as such can generate greater profits in a short amount of time.