The only time I hear or see anything about cloudinit, it is always a problem.
Nobody ever said "we don't need worry about that, cloudinit takes care of it".
In this particular case cloudinit presence in the story is incidental, delivery mechanism of said config file could have been different.
It's useful for initializing state that could not have been initialized before booting in the target environment. Canonical example, I guess, being ssh server and client keys management, but the list of modules it implements is long.
What good does cloudinit do really?