Investors who are not too old of age can bliss on partial withdrawal and decide to reinvest percentage of their portfolio back into Bitcoin, practically for those who started by DCA approach this should help strengthen their portfolio.
If you know that you are still in a stage of accumulating bitcoin, I would be cautious with any approaches that sell BTC with expectations of buying back lower, since those kinds of strategies might lead you to employing too much waiting to buy BTC and not enough actual buying of BTC. One of the most assured ways of continuing to grow your quantity of BTC is by continuing to buy it.
It totally depends on what price he sells his BTC. Something that is moving up is always going down, too. It's kinda stupid when someone sells his BTC at a low price. Then hopes to buy it back at a lower price.
A smart trader'd be shorting with very low lev while waiting for the price of btc to dipping. And wait for a good price to entry.