Does `parent` provide any advantage over running `exec`?

I recently learned about Caddy and I'm evaluating it.

I noticed it uses this `parent` utility in places where I would expect `exec` to be used.

The documentation does not mention what advantage `parent` has over `exec`. A disadvantage is certainly increased complexity and one extra process running, but I fail to see the pros here. IMHO documenting them in the README would be great.