In addition to criminal activities, bitcoin is also used for tax evasion as it ensures absolute anonymity.
How can you say that? Bitcoin is not really anonymous. Think of it, a lot of criminals are still being caught even if they are using Bitcoin. It can still be traced, you just need to search for that to know it.
Bitcoin is not a criminal tool either since Bitcoin is not really a currency to be used in such activities. There's just a lot of people that are taking advantage of these digital currency to escape their illegal activities such as money laundering.