Honestly, depends on your long term investment strategy.
Do I think crypto will return greater than 20% in the next year- most likely. However it could just as easy go the other way (my crypto holding is down 18% today).
Do I think it will always give returns this high- probably not, however as adoption increases the price will continue to climb until such point adoption manifested.
I do not believe that crypto is seen as a “currency” as of yet but rather a speculative bubble.
Investors need to be willing to lose everything investing in something that is not backed by any organization such as FDIC. However, it comes down to no risk = no reward.
You need to determine your risk appetite and be sure to diversify your investments, or simply put, not put all your eggs in a single basket.
I think that once it is widely adopted it will then take the form of a currency, but for now I would not be surprised if crypto becomes the new “gold” standard.
I think the argument for 2018 is not whether crypto will continue to go up, the question is what coin will do the best.