Investing in bitcoin is not a big risk, if the government of different countries are investing in gold as reserves for their national tresury, what do you really think makes investing in bitcoin more risky?
Gold has longer history than Bitcoin and Bitcoin price is more volatile than gold price. Managing a personal, company portfolio is easier than managing a national treasury, and countries have to be more careful with their national investment in Bitcoin. If anything is wrong with Bitcoin, like its price collapse, a national treasury will be in trouble, if Bitcoin is a main part of their national treasuries.
Bitcoin is good for an investment portfolio but there are many things that affect decisions like invest or don't invest.