It is just propaganda.
The risks of the bitcoin trading warns by government's countries such as : many criminals used virtual currency as a tool for money laundering.
What do you think criminals use more, cash or Bitcoin? Bitcoin is pseudo-anonymous, cash is completely anonymous.
Second, virtual currency is a digital form, so the risk of hacking, stealing, changing data is huge.
Most money is held in banks these days. Banks get hacked all the time. It is a lot easier to hack a centralized bank than decentralized currency. Bitcoin is a lot more secure than other digital forms of money, like PayPal, banks, credit cards...
Third, virtual currency values fluctuate continuously, so the investment risk is so high.
Fiat doesn't fluctuate, it only steadily decreases in value due to inflation.
These are still the early days for Bitcoin, it is obviously still not the optimal currency, as adoption needs to grow so you can actually buy stuff with it.
When the adoption gets big enough and a big portion of population starts using it, the price will stabilize.
Supply is very predictable and stable, it is demand that fluctuates, but when demand stabilizes, as everyone who wants to use it, acquires it, then the price will stabilize as well.
Fourthly, virtual currency is an asset that has not yet been managed by a state management agency. When a dispute arises, the legal safety of participants is very difficult.
This is exactly why it is so popular and why it exists in the first place. Who do you trust more, mathematics that Bitcoin is based on or politicians?
People don't trust politicians anymore, they trust technology, this is why Bitcoin is what it is today and what it will be in the future.
Hence, there are some of financial specialist in called for governments to regulate and tax bitcoin, labelling the cryptocurrency an object of speculation and a tool for money laundering.
And this is exactly why they are spreading this propaganda. Safety is bigger with Bitcoin, this is obvious to everyone who knows how it works, it is the tax part that governments really want. They are like one big mafia, they don't like competition. How they earn money here is racketeering, you pay them protection money and they don't bother you.