On or after the 'copied value' automation

When making an automation to test this I do have results in my dropdown for "the value in the field" that were other dates. With dates I have found that what usually happens is one field is a Date field and the other is a Date/Time and they do not like to coexist. I was comparing Date Created to another date/time field in this case.

I had never seen this before. As far as I can tell "the copied value" seems to be the value from the record that triggered the automation. Looking at the Automation help guide it mentions this under Adding or Modifying a record "For each field, you can type in values, copy values from other records, or combine typed and copied values. When you choose copy, your automation will retrieve the value from another record and insert it into this record. In the Value dropdown, select a placeholder value. When your automation runs, this placeholder will be replaced with text." so that leads me to believe copied values are just values in the trigger record. It also lets you select if the value is from the old(before change was triggered) or new record in this way, which is different than what you get when you say "the value in the field."  It is worded in a really strange way though.