They listed exactly what they are doing. The artifacts they are picking out should already be tagged with the release. The script to push those to production can use those tags to know what to push and what git commit hashes to check.
ETA: I'll add that when pushing production, the amount not just you can waste, but everyone down the line from users, developers, testers, etc, etc, can be huge. Calculating how much time you would save isn't useful.
ETA: I'll add that when pushing production, the amount not just you can waste, but everyone down the line from users, developers, testers, etc, etc, can be huge. Calculating how much time you would save isn't useful.