The first depends on your own choice, if you want to invest in the long run, of course you should be able to be patient waiting for the price of coins for a long time or at least until the price actually increases. different from the short term you can easily get short profits but very high risk.
Long term and short term both are high risk but this depends on how the traders will employ his strategy.
There's no one prove that short term is less risky that long term because at the end of the game, we are just all gambling with the prediction game.
if you are not good enough to do short term, then long term will best suit of you as its simple to do, it's just a buy, hold, then sell at the right time.
However, there are also times that our target will not happen even if we hold for a very long period already, that's where we will have to evaluate everything if we can still continue to hold.