That impinges on someone else's freedom. I'd go with something like selling 2 kidneys or contracts that result in indentured servitude.
Everything we do impinges on someone else's freedom. Being legally allowed to walk in the street? Impinges on someone else's freedom to block me from walking in the street.
It is always a tradeoff. In the case of the particular tech discussed, it's a tradeoff between being able to somewhat control crime (e.g, making payment for human trafficking harder, making it possible to reverse theft) and financial privacy. It's freedom from having things stolen and freedom from being regulated.
That's just a slogan. The devil is in the details. To use an extreme example: Murder laws removes my freedom to kill random people; how is that good?