I think Bitcoins saving is quite risky, because compared to other forms of investment such as gold or dollars, cryptocurrency is more risky because the possibility being hacked is so high, we could be stolen bitcoin or the ability the network system attacked, you lost all bitcoin in the second. In addition,fluctuations in bitcoin price are highly impacted by the market so investment in bitcoin is unsafe solution. 
Oh Dear, please, please read around the forum before posting such stupidity. What do you mean network system attacked? Do you have any idea what you are talking about? Maybe what you heard about people losing their bitcoin is (1) they put their funds on a exchanges, so when a hacked happened on that exchange, your money is gone, (2) you didn't protect your wallet, - password is not strong, or you give your private key to someone untrusted. Fluctuations is part of the nature of bitcoin, If you don't know how to handle fluctuations, you shouldn't be in bitcoin investment. Bitcoin price is based on supply and demand, so its another factor that you need to understand before talking about fluctuations, volatility and unstable price.
Sorry for causing the indignant from you all, simply after for a while I study about bitcoin I think that the main reason is because of its great value, so many people will do whatever thing to trade, buy or seek even stole ... to get them, that may also be the reason why it's not safe.Similar to stocks, which give you big profitable, the risk is the same, you may become a billionaire, but you can also be empty in a few seconds. I just want share my idea with you all in this community !