Factors that influence the value of the bitcoin:
1) government bitcoin policies and laws
2) political situation
3) social trends
4) appearance of new competitors
5) artificial influence on the value by trading at the crypto market
6) news (not always true one)
and many more. Could be something new will appear in the future. Did I miss anything?
Your absolutely right. Even in any investment opportunities, all of this factors will always affect the decision of the investor, seller, buyer. May it be in stocks, forex, etc. The biggest part of this in cryptocurrency are the news going around the policies of certain countries. Well, you just have to do your own due diligence to take care of your decision.