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> This is a misconception and if you think about it, it doesn’t make a lot of sense since the two records are generally generated by a system that gets a single value from the user, so it would be a software error if they did not even out.

That applies to a software system, but not a handwritten ledger. In the latter, it does serve as an error detection mechanism because a human has to enter both values and other humans have to read them clearly.

You are correct, though, that the primary reason for double-entry is audit trail.

> However, double entry accounting gives us an audit trail because it tracks how assets are moved between accounts.

Ah, makes sense. My understanding of double-entry comes from history rather finance. I read a few articles on Italian history, specifically the Medici family with Florentine banks and hand-written ledgers. I'm not an accountant, in practice it makes more sense as an audit trail.

I guess you could stretch the metaphor further and say that a SCM + testing gives you the equivalent of double-entry. However in practice, I've never had much trouble convincing anyone to use a SCM :).

Double-entry accounting predates software implementations thereof. When writing values by hand into two different physical ledgers, it would serve as a limited form of error detection.