Both long term and short term are good for investments. Bitcoin is good for both long term and short term investments. At the same ethereum and other altcoins are good for long term investments. Always long term investments only will.give more benefits. In short term investments we cannot analyse the market moves. But in long term we have a time to analyse the market whether it will be in increase or decrease mode. According to that we can plan ti hold or sell.
No one has any idea where the market is going but over a decade, Its likely going up if history is any guide, That's the difference between long term and short term investing, Short term is unclear. Long term is historically a pretty good bet.