This is late, probably too late, but if you really want to get into the weeds of this, here is a better summary that what I can produce, from a paper that explains it better than I can:

"The model is a work of fiction based on the tacit and false assumption of frictionless barter. Attempting to apply such microeconomic foundations to understand a monetary economy means that mistakes in reasoning are inevitable." (p.239)

https://academic.oup.com/cje/article/48/2/235/7492210