In terms of micro, yes there are pretty consistent theories as to why and how people use money. Probably the most relevant application thereof are in the microeconomics of banking and in so called microstructure models in finance.
In terms of macro, there is of course also a lot of monetary theory as to why people use money in a certain way.
What does not yet exist is a unified theory linking micro behavior to all aggregates. Such models typically rely on some sort of representative agent, which is known and recognized to be deeply problematic in scientific terms of aggregation. Other approaches exist, of course, such as agent based models. But there is no "theory of everything" yet.
Can economics give rationales? Yes. Peek into any course on the theory of money.
But reasoning from micro behavior to aggregates is difficult in social science. We are currently in the process of figuring out better theories of aggregation, but doing so requires using game theory and decision theory in fully interdependent (so for example networked) contexts trough dynamics, so this as of yet also requires a lot of methodological (read: mathematical) machinery that is not yet developed.
Inverting the question does not obviate the answer to what I asked you. Moreover, as stated your rebuttal question is underspecified: what do you mean by the "dynamics of money" and "stable foundation"? Can I trivially answer this by talking about the relationship between credit and debts, or are you looking for something more specific? You responded to my (very precise and specific) question with a vague, orthogonal dismissal of the entire field.
Why don't you tell me about the "mathiness" in some peer-reviewed economic paper (preferably in a tier 1 journal) that you perceive to only be correlated with real world conditions in "very narrow circumstances"?
Can you give an example?