I do not think we can get a huge profit in just over 3 years, compared with a mutual fund that takes at least 10 years to get 200% profit or gold that takes more than 25 years to get 100% profit.
Saving bitcoin for a longtime is good because they have possible the price decrease. Lets back last few years ago the price is very low and if you hold bitcoin for few years you will earn profit. So holding or saving bitcoin for longterm is worthy or they can get big profit because of bitcoin. More bitcoin that you have more money to come with you.
I think that you putted a wrong word there, you putted 'decrease' instead of "increase". The bitcoin is very good for long term because of the continuous amount of gains in price that make the market healthier than before. With the progress of bitcoin, it already made a lot of rich person in the world of bitcoin because of their patience and faith in bitcoin that really pays off.