the main danger is the unstability of the currency. sometime the price touches high and sometime price drops down to even 90% or less so investor get heavy loss for that.
We need to have a mentality to accept losses too. Important factor with bitcoin is the price varying in respect to time. I personally like the fluctuations, none other than bitcoin has got such feature. If the price is stable we cannot make better profit. Things are dangerous based upon the way we take it.
Definitely the price is our basis to trade and to earn from its volatility but I think that is not the after of majority of adopters in bitcoin. It's just an investment for certain number of people while mostly if not all of the adopters had enjoyed using bitcoin regardless of our purposes.
The danger is when we are just sleeping and we are not monitoring the market, we will certainly without with nothing if something bad happens.