I think we shouldn't doubt about the stability of the crypto currencies over the mid-term. However, Bitcoin still has strong downside potential and I don't rule out its sharp fall in the near-term. For a new bullish trend of BTC will require high demand from a both retail and institutional investors, which we saw in Q4 2017. But taking into account the BTC's trajectory in the past six months, I think that Bitcoin's best times is in the past. So my view on BTC is bearish.
I'm skeptical on the fair value of Bitcoin. In my view cryptocurrency price action and investor behavior fit the classic definition of a speculative bubble. I see agiotage with crypto among mainly retail investors as omen of misfortune - buying anything ending in .com in 1999. Another problem is limited use of cryptocurrencies, which mostly use in places with unreliable banking systems and dark markets. When the market of crypto become regulated, interest in Bitcoin and its peers will be lost.
I think, that the fair value of Bitcoin is much higher than today's price and the risks are exaggerated. The potential reflects the markets which Bitcoin could challenge: (1) Bitcoin disintermediates the transfer of money across borders, so correspondent banking could be substitute by Bitcoin, (2) Bitcoin could also be a very strong competitor to the credit card companies, (3) Bitcoin is similar to a currency, so it could take some market share from fiat currencies. Also I expect that the number of institutional investor will rise over the next 18 months.