Sometimes holding is good and other times holding is a bad idea, there are some project if you don't sell at the time the price was high and holding thinking price will go even more higher in future it won't because by then the team must have dump too and left the project, you will be holding a bag of shit coins.
that depends on where you are and how good or bad your position when you were entering the market. Holding sometimes can be profitable but there were so many people who have been losing a lot caused by they were getting trapped at ATH. that makes them all can't go out from the market.
when we hold some coins or token we have to understand what is actually going happen to this project. dont ever we hold but we dont know what happen to projects. some investors often do this mistake, while they buy and decided to hold but forget without find and update. if we know the lastest fundamental we will understand what should we do later.