I think both are as good. long term or short term just the same for me. if you have a lot of capital you can save some potential coins for the long term. and part of the capital you can trade short term. that's what I have done so far.
It depends from the bustle at had by everyone, if we have a high bustle then better choose a long term investment,
but if we have a lot of spare time then I think the short-term investments (trading) are better than long term investment.