One reason that has not been given, but may be the actual reason why many people buy and hold Bitcoin is its use as a betting instrument. That is, you buy it paying X dollars today in the hope that you will get >X dollars when you sell it at some time in the future. Of course, if it has no other value than that of a betting instrument, then this is really a game of "holding the bag" with the last people out getting screwed.
Why people buy bitcoin and hold Bitcoin because of Bitcoin is a digital currency that is decentralized I did know person can change it is also holding cryptocurrency is something that concerns future because when holding cryptocurrency especially Bitcoin and it price increases automatically you will make your own profit from the price going up so that is why people like to hold Bitcoin for a long time so that they will able to see when the price is high