1. Lethargy during a sideways market
2. Disregarding your strategy
3. Chasing somebody elses dream
4. Believing somebody elses FUD
5. Using money that you shouldnt be
6. Failing to properly do a self risk analysis before investing
If you can cope with these dangers then this type of investment will do well for you. This is a hands-off, long term method of investing. DYOR, find good coins with bright futures, buy and hold. Dont worry about the daily percentages
If there is no hodler of coin, probably prices moves down until it becomes 0 value. I believe that there are dangers in holding coin per individual person but it helps a lot for the community to be strong even there are storm. If we always hold coin and does not sell it at low price then we will make dollars of money.
Sometimes it is holders who are saving bitcoin from destruction and sometimes investors are the pillars who work day and night to engage so big audience by manipulating the prices to keep market alive. Just think how it would be when market is down, and no movement is being observed by anyone. It seizes to death. So awakening market is compulsory.
Traders and holders have their own role for the bitcoin market, there are tens of millions of users in the bitcoin, whether it's a holder or trader but both are equally helpful. you don't need to worry if there are too many holders, when prices are without movement, the holder makes bitcoin stay alive, there will always be investors or trader, and price movements will definitely happen always, dont worry.