Answer:
Having a lower risk of complete damage.
Explanation:
The advantage of having the phrenic nerve come off the cervical plexus rather than directly off of the spinal cord is having a much more lower risk of losing the function that it provides which is breathing, crucial for the body.
As the nerve coming off the cervical plexus can not be damaged completely, unlike the spinal cord, it can still continue to function at some level.
I hope this answer helps.