[JumpCrisscross]

> the transaction price of "centralized currency adoption" is not a priced object

Of course it is. Joining a currency union carries costs.

Broadly speaking, you're correct: the term has ambiguous meaning. My point is that isn't something new, but an element that has always been with the term.

[s1artibartfast]

I think that still runs afoul of the "uninvolved 3rd party" part of the definition.

Two actors can both generate value from a transaction due to a difference between price and their respective utility value for what is traded. This producer and consumer surplus is explicitly distinct from externalities.

If there is a currency deal between the US and Argentina, the consequences to those countries are not an externality. However, if this deal produces a 2nd order change in the Chinese RMB, some would call that an externality, although I would call it a consequence (because externality implies mispricing)