Not everyone invests for holding purposes. Some people are day traders, they just trade to make profits daily, they are those that sell their coins easily. There are others who are holders, but holders are the best, I will advise you to hold.
Actually, between the holder and the daily trader are almost the same, it's just that the daily trader holds the coin in the daily run, while the long-term coin holders usually invest a little more than the daily trader.