The substance of money

Not much epistemic effort here: this is just an intuition that I have to model a vast and possibly charged field. I’m calling upon the powers of crowd-finding to clarify my views.

Tl;dr: is the debate in economics over the nature of money really about the definition or just over politics?

I’m currently reading “Money—an unauthorised biography” by Felix Martin. It presents what is to me a beautifully simple and elegant definition of what money is: transferable value over a liquid landscape (these precise words are mine). It also presents many cases where this simple view is contrasted by another view: money as a commodity. This opposition is not merely one of academics definitions, but has important consequences. Policy makers have adopted different points of view and have becuase of that varied very much their interventions.

I’ve never been much interested in the field, but this book sparked my curiosity, so I’m starting to look around and I’m surprised to discover that this debate is still alive and well in the 21st century.

Basically what I’ve glanced is that there is this Keynesian school of thougth that posits that yes, money is transferable debts, and since money is merely a technology that expresses an agreement, you should intervente in the matter of economics, especially by printing money when this is needed.

Then there’s an opposite view (does it have a name?) that says that no, money is a commodity and for this reason it must be treated as such: it’s creation is to be carefully controlled by the market and it’s value tied only to the value of an underlying tradeable asset.

I think my uncertainty shows how little I know about this field, so apply Crocker’s rule at will. Is this a not completely inaccurate model of the debate?

If it is so, my second question: is this a debate over substance or over politics?
If I think that money is transferable debts, surely I can recognize the merit of intervention but also understand that a liberal use of said tool might breed a disaster.
If I think that money is a standard commodity, can I manipulate which commodity it is exactly tied to to increase the availability of money in times of need?
Am I talking nonsense for some technical reason? Am I missing something big? Is economics the mind-killer too?

Elucidate me!