I specifically stated it was an unsophisticated example. GP wanted to know what happens with the "simplest transaction" when he buys a banana.

Yeah, exactly. The first or second example in any explanation should be buying a banana that you immediately eat. That way the reader sees that an "account" doesn't have to be a bank account nor even a collection of physical goods that exist, it's just a virtual bucket made to keep track of certain transactions. Until I figured that out, double-entry made no sense at all. This is all exacerbated by the common "Assets = Liabilities + Equity" equation which hides expenses entirely. All of this is, of course, a problem about pedagogy in the quick guides found all over the internet. (Including the one linked to here, though the second example is at least an expense but not in the way that would enlighten a beginner.)

That was the simplified version.

Apples and oranges. By way of analogy, the OP was talking about C while you are describing building a commercial Windows app. DE accounting is a simple tool that can be used in complex ways.

OP is neither, it is in Python, but this merely demonstrates that accounting can be incorrect in any language.

The problem isn't just terminology, but when people use the term double-entry accounting interchangeably with double-entry book-keeping, they reveal how little they know about the subject matter, and how unqualified they are to be implementing either.