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So there is different opinion among people about Bitcoin. Some people consider Bitcoin as "criminal money" because it's often used on the dark web and helps criminals to get away with selling drugs and stuff.
~Like would it be good if we could create a system that somehow will make the life of criminals who use Bitcoin harder?
Bitcoin does indeed used for bad things, but it does not imply that it is meant to facilitate those things. The main issue that you raise about limiting Bitcoin usage in order to eliminate criminals might have unintended consequences. If we specifically reserve a centralized entity to make anyone able to censor a transaction, it is very likely would make Bitcoin lose its significance.
It is necessary to look at another thing when you have that kind of mindset. Say, a simple thing like a knife, if it is used to kill people, do we surely want to somehow restrict its usage?
Actually, in Bitcoin, miners are able to include or exclude a transaction, so practically, there is a way to exclude alleged criminal usage. Nevertheless, how does someone make sure that it is indeed an illicit transaction?