With automation you can replace digital certificates in no time and prevent outages in case an administrator forgets about expired certificates and is not able to replace those.
If you are looking at automation in regard to PKI, there are four areas in security where automation can be applied: Efficiency, Security, Crypto-agility, and Compliance.
Here is an example where automation helps. As we are moving towards digital transformations, the number of certificates being used in any type of enterprise is increasing. Contradictory to that, the life cycle of certificates and their expiration of those certs are getting smaller. That means you need to deal with more certificates and short life certificates. With automation, you can replace those certificates in no time and prevent outages in case an administrator forgets about expired certificates and is not able to replace those.
Human errors are playing a big role in security. Imagine that you have thousands of certificates, and you need to configure each one of those manually and individually. This will create a surface of error where an individual will inject inaccurate data into a certificate request before the certificate is issued.