Answer :
The advantages to having a civil service system to select government workers is that it eliminates the aspect of it being hereditary. Meaning, you won't automatically get it because of your relation to the previous worker.
I believe the answer is: that it eliminates the aspect of it being hereditary.
Because of this system, you won't automatically get the job simply because of your relation to the previous worker (practice of nepotism).
With this system, the government could obtain the more competent workers which is much more likely to produce greater work results.