Inherit parent metatags as placeholder in override forms

Thank you for this, since years, essential and very very great module.
I hope my guess is NEW and was not posted already. I searched the issue que but didn't find a related issue.

What I'd like to suggest for the 8.x version with its empty fields by default when overriding a parent configuration:
Set the parent field value as HTML5 placeholder for the form fields to show what's the current active configuration for the field.

Example:

Global "page title" has: "[current-page:title] | [site:name]"
Node entity override was not set yet. Set "[current-page:title] | [site:name]" as placeholder there if the field is empty / new. So it's easier to decide where to change the inherited value without using a second window for the overview.

The same could be done within the entity fields.

In Drupal 7 the fields were always prepopulated with their inherited text, but I think the combination in Drupal 8 is much better and clearer. Shell I create screenshots to make it clearer or did you get what I mean?

I think this would improve the workflow, what do you think?