I think the main issue is the concern of decentralization of Bitcoin. The government cannot monitor where the money is coming from (and going to). Hence, it is risky and prone to money laundering (which most of the time related to crimes and illegal activities). There are also concerns regarding the monetary policies which regulate the flow of money in the market which is important in handling inflation and prices of goods.
In related to this, we are just doing trial and error as of the moment - finding the right balance of decentralization and government policies to provide limitations.
Regardless of any issues about decentralization or not, Bitcoin is a pretty good accurate source for everyone who needs it. If it is placed on an exchange, the money may be tracked because there it requires KYC and it is easier for the government to track it, unless it is stored in a wallet which does not require KYC. The problem of money laundering has occurred long before bitcoin was developed and perhaps not everyone commits this crime, it's just that some individuals use bitcoin for their criminal activities.
I don't agree if bitcoin is considered a crime because it is related to the individual perpetrator and when people don't try to commit crimes involving bitcoin then everything will never happen. Crime has been happening long before bitcoin was developed and there is a lot of illegal activity going on. The question is why is Bitcoin so in the spotlight regarding this crime?