Yes holding bitcoin for long time is a very good way to earn more money but you should have that patience to hold your coins. normally people just keep spending their coins and trade a lot because they think they can earn more money in very less time. this is a problem with most of us.
of course it is a good idea to hold bitcoin for long time because the price of bitcoin i think in future will be very high and those people who have hold their bitcoin they will be very lucky and will have a big profit and also you are right that holding bitcoin need patience because the price of bitcoin sometimes become very low and some people lose hearts and sell their bitcoin, so be patient in holding bitcoin it is a good way to make money.