Although the question is simple to hear but answer is not so easy because there are so many coins in the market to treade for short term.But I think bitcoin is unique one among them.
Yes there are a lot of coins in market and they all better work for people but bitcoin is much better and I also like this currency for earning because bitcoin is the king of every coins and if you invest in bitcoin you will never discourage about your profit so that,s why trading in bitcoin is also beneficial for you.