Crypto isn't effective against governments. They can just ban it, and since most of them publish all their history in public forever they can find you using it.
It's only useful in situations where it's legal and yet some private actor is not letting you use bank transfers for something. Porn and weird research chemicals maybe.
If I live in one country where it is legal and I travel to another country, where it is illegal. Do you actually think that will stop me from being able to use it?
Due to market forces, it is often easier, and a lot more powerful, for me to use it in the banned country. Once I'm in that other country, I'm also anonymous again.
> Do you actually think that will stop me from being able to use it?
Yes. Obviously you can't do infinite financial crimes by traveling to another country and doing them there. For instance, they can get you the next time you want to travel there.
In this case you also can't use local exchanges if they don't exist and you have to evade the Great Firewall.
It's only useful in situations where it's legal and yet some private actor is not letting you use bank transfers for something. Porn and weird research chemicals maybe.