How safe is it?
According To me Its Not Safe to Invest Your Money Into Bitcoin For Long Term Because Bitcoin Price is Not Stable And You Can Lose Your Whole Capital If the Price Crashes.....
According to me Instead Of Investing Your Money In Btc For Long Invest it For Short Term So You Can Hope To Make Some Profit.....
But for me , although bitcoin's price is unpredictable and seems fluctuate holding in long-term is good. Just often check the bitcoin's price and if you think you can get profit you can sell it afterwards and buy it again if reach your preferred prices.
Buying and selling on regular basis is the best way to play with your coins instead of holding them for long term as we don't know that holding will be profitable for us or not as it will totally depend on the price in future.