Simple text fields can be shown adjacent to references to an entity in other rich text fields when you reference them with #. Rich text cannot. If Rich text could, I’d gladly use rich text.
Meaning I can do the following by referencing an entity in any rich text field:
#Project 1 - [simple text] - [assigned user]
But I can’t do:
#Project 1 - [rich text] - [assigned user]