…if you want things inconsistent.
Automation ensures repeatability.
If you have a manual process, that you want to do manually — because reasons — you may be able to do it somewhat identically 10 or 100 or even 10,000 times. But if that process changes (it will), or you get forgetful (you will), or you make a simple mistake (you will), or die (going to happen), then it’s most certainly not repeatable.
Also, a few words on “reasons” — they’re quite often just excuses and justifications for remaining static.