They save bitcoin for a long time because they know that the Bicoin price will go not double, triple but 4-5x it's price of today. Just like 5 years ago many people ignore bitcoins just look what's the value of it today many people invest bitcoin past years ago and look at them now, they're now rich because they wait for the right time. The benefit of saving for a long time is the longer you hold your bitcoin the more richer you're going to be in the future.