Shell companies are one of the greatest instruments for graft ever devised. I'm not a fan of them, and they get easier to make with every passing year. I don't have an opinion on cryptocurrencies. I'm sorry if it seemed that way.

Yes, there is a hazard in this. But probably also lots of utility for benign causes. So I hope they will outweigh the malicious ones.

I'm curious how you launder money in bitcoin. If you know that some btc was used for a "criminal" exchange, then you can track all the Satoshis through all their recipients. You can just blacklist the money in your country and any retailer using your blacklists would not accept it.

One example how it can be done: https://news.ycombinator.com/item?id=8130592

I mean in a bitcoin economy. The only reason that example works is because the input fiat does not have the transparency of a blockchain behind it. If you were end to end using bitcoin, ie, drug dealer gets paid in bitcoin, then if you know its drug money you can blacklist it forever because its always traceable.

There are ways around that: https://en.bitcoin.it/wiki/Mixing_service