I didn't know those existed, and so I kind of see your point.

The counterpoint is that if your job was to prevent/punish financial crimes that affect consumers, would it make sense to ignore these exchanges?

Heck, if M:TG cards were the medium, and they could be moved across international borders with a few keystrokes, then surely those would be watched too.

I won't argue that it's not privacy-invading for legitimate customers, but if the legal structure allows it, regulators have an obligation to look where the problems are expected to be.