The evidence chain is the link from anything the platform tells you back to the specific records it came from.
A number is not presented on its own authority. An observation about your margin can be opened to the jobs behind it; a cash figure to the transactions; an alert to the records that tripped it.
Why this is worth having as a rule rather than a feature
Because the alternative is trust, and trust is the wrong basis for a decision about your own money.
Software that tells an owner their margin fell without being able to show which jobs is asking to be believed. When the figure looks wrong — and sooner or later one will — there is nothing to examine, so the choice is between accepting it and ignoring the whole tool. Most people ignore the whole tool.
With the records attached, a figure that looks wrong resolves one of two ways: the calculation is wrong, or the underlying data is. Both are worth finding out, and neither can be settled by arguing with a screen.
What it is good for
Checking something surprising. The first useful move on any number you did not expect.
Finding data problems. Very often the records show the figure is right and the input was wrong — a job never costed, a transaction never categorised. That is a more valuable finding than the original number.
Explaining a figure to somebody else. An accountant, a lender, or a partner asking where a number came from. See tax documents and packages, which assembles the trail for exactly this.
The limit
The chain proves where a number came from. It cannot prove the number is right — only that it was calculated from those records.
If the records are incomplete, the figure is confidently wrong and fully traceable at the same time. Which is why how Omnyra reaches a number says plainly that traceable is not the same as correct, and the most common cause of a wrong figure is something that was never recorded.