Anyone taking profit from his bitcoin investment with the idea of buying back when the bitcoin price dumps is taking a great risk because that person will not be patient enough to wait for the bitcoin price to dump so that he or she can buy back his bitcoin because the bitcoin price keeps going high. FOMO will make that person buy back his bitcoin, even with the profit the person took from his bitcoin investment, just to be among those who are holding bitcoin in case bitcoin does the unbelievable. The person will be buying back less of the quantity of bitcoin he or she sold out because of the high price of bitcoin.
People doing that is not really for long term since if they aim to hodl they would never think about selling their bitcoin when they see a pump and think about buying again when the price dump. The person who doing that are traders and I guess there's really a high risk for them to lose their money if they repeatedly doing this schemes. And won't recommend this to newbies especially if they don't know what to do next and much really better to anyone if they just hold their bitcoin and aim for long term since this will give them more decent result, also for that they would not get affected on any FOMO circulating around.
On the other hand, yes, basically our intention and purpose of getting involved in investing is to make a profit in any way and one of them is by buying when the price drops and selling when the price is high enough, I think it doesn't matter because it is indeed a method that many investors choose, and also every investor has their own choices regarding the methods and approaches they have to their bitcoin accumulation. So maybe I will not say that the short-term method is wrong, because if for example they are able to maintain and balance the following as well as knowing what to do everything well it is good and will not be a problem, but maybe the difference is in terms of profit is not too maximum between investors who always cash out in the short term and investors who always maintain their bitcoin accumulation in the long term such as 10 - 15 years, the difference in my opinion is because when you choose a short-term method there will be a slight delay in terms of profit while it will not happen when you always choose to maintain and have a long-term approach.