A dollar is an entirely fictional unit and trillions of it can be manufactured at no cost, while watts are constrained by the laws of physics, photons/electrons, supply chain of electricity and all that fun stuff in the real world.
If the abstraction works better for you this way, call them interchangeable units of American and Chinese insolvency. Or incremental forfeiture of domestic ownership.
It’s still a useful proxy for resources allocation and viability.
While we could reason in "performance / watt" and "performance / people", "performance / whatever other resource involved", and "performance / opportunity cost of allocating these resources to this use case and not another", "performance / whatever unit of stable-ish currency" is a convenient and often "good enough" approximation that somewhat encapsulates them all.
A simplification, like any model, but still useful.