selling a portion of it will make more sense than selling all of what you got in your portfolio. It is an investment that’s already projected to grow overtime and not a short one.
In terms of investors selling there Bitcoin holding I really don't encourage that idea but however if an investor must sell, it should only be in a case or in a point were the amount of Bitcoin they have accumulated is big enough that even if they decided to call it an arriving point of there Bitcoin investment it will be okay, so perhaps that's why even if most people have that mindset of selling it should be when they have gotten to there accumulated targets, then they can decide if they want to sell a little part of it or not, though if the investor has other means of survival I think holding all the investment will be better because as time goes by that's how your investment is appreciating.