In my opinion, taking some of the profits from altcoin investments is a good move when the price rises. it is an opportunity that cannot be missed because we don't know whether the price will continue to rise or even when it will reach its peak. Therefore, while the price is rising and it is profitable, take the opportunity to make a profit.
That's what the majority is doing.
Those that can't dispose their altcoins and turn them into profit are holding it for their own purposes. Maybe the profit isn't enough for them to cover.
Or, they've got some other better plan that's being on its way as they hold it. But if you ask me, as long as you're happy and you're in profit, please do.
You might not see those opportunities to come again as the market is very different with altcoins than of Bitcoin.
I also suggest that if you have made a profit from an altcoin, whether it is 10 or 20 percent, then it is better for you to take the profit and not try to hold it any longer. The altcoin market is very risky and when the price has been pumped up there is a possibility that the price will fall again as has happened with the Manta project.