The biggest risk of using Bitcoin is it's price. It's price is unpredictable anyone can't guess the future price of bitcoin it will lose or dump you can lose and earn from it but it is risky.
Not just Bitcoin, it is difficult to predict the future price of any virtual currency. However, the future of Bitcoin depends on the investor presence in the market. If the government of a country renews bitcoin Only then does the market change. Moreover, there is no other risk in investing in Bitcoin.