There are allot of manner to earn allot of money with coins and that is really easy you can invest in coins and not spent any of them wait till he rises or you can invest into companys to get nice %.
Holding is really not profitable compared to daily trading which ensure that you gain profit,if you look at how much you can earn compared to holding you coin trading daily is much better.
Trading involves risk whereas holding is risk free, if you want to really play safe then holding is the best option, but holding should be limited as holding too long can also be risky if price drops in future.