We (and many companies) use icon only buttons in our app. When writing content, we often have to write things like "select the pencil icon to edit".
I'd love to be able to insert an icon in-line with the copy so the user can view what the icon button looks like.
I noticed Figma use this, and it makes the content easier to read as you can identify the icon (see screenshot).
I would expect that to use this feature I'd either need to upload a library of app icons, or copy and paste SVG code or something.