The mechanical benefits of product-as-code are easy to describe. The cultural one is larger and harder to sell in advance: product decisions become reviewable.
What changes
A definition change is now a diff. Someone proposes that "settlement" means something slightly different, and instead of editing a wiki page silently at 4pm, they open a pull request. The people who care get notified. The change is discussed in the open, against a specific proposed wording, and the discussion is attached to the change forever.
Compare that to the wiki, where the same edit is invisible unless you happen to watch the page, and the reasoning exists only in whatever meeting produced it.
The gate carries the boring half
The reason this is bearable is that the machine handles everything mechanical. Reviewers never check whether ids are unique, references resolve, or the bundle was rebuilt. Those are PAC-01x, PAC-020 and PAC-060, and they are settled before a human looks.
What remains for the reviewer is the only thing a human is better at: is this true, and is it the right call?
That is a good use of attention. Most review processes fail because they spend it on things a script could have done.
Blast radius is visible
Because the bundle is committed, the diff shows the consequence. Adding one see_also changes one line. Restructuring a type changes four hundred. A reviewer sees the size of the change before merging, which is exactly the signal that free-form documents never provided.
Who should review what
Terms and rules need domain review, not engineering review. The people who should approve a change to TERM-settlement are the ones who will be wrong if it is wrong -- which usually means finance, or support, or whoever answers customer questions about it.
CODEOWNERS handles this. Point product/terms/ at the domain group. Now the right people are pulled in automatically, and the ones who do not care are not.
The failure mode to watch
Review can become a bottleneck if every trivial wording fix needs three approvals. Keep the required-reviewer set small and let the gate do the enforcing. The goal is that changes are visible, not that they are slow.
Visibility is the product. Ceremony is a cost you should keep paying down.