all kind of investment has a high risk, not totally safe I mean. so don't considered bitcoin as safest investment but considered is as a possible passive income for long term, because bitcoin had to face ups and downs in price in the future, if you mind those trend you will lost your money but if you endured that and still holding your bitcoin what ever happen, you can earn a good profits at the end of your achievements. again, there is no guarantee that bitcoin is safe for investment,