You should to hold ethereum only just it so usable now in all cryptocurrency world. But, if you would, you just should to hold it for short terms. It's the best variant for ethereum.
Probably it will be the best solution, although short positions need to be able to analyze and open / close. In principle, investing in this coin makes sense and still has prospects, because all the same the network is planned to be updated, the platform is live, work is on, and therefore everything is not lost