Suggestion:
Allow retrieving the direct link to a non image file, sometimes it is required for integration with other extensions. For example to embed a video using embed video you need to be able to link to the file. Of course once it's uploaded I can go and manually figure out the path, knowing the filename after upload and the date (directory), but it's manual work. That could even be an integration with the new media manager under the pending PR (get link from uploaded item?)... not sure the best way to accomplish this.
Also it would be nice if upload images were displayed in email notifications like externally linked images. I guess the markdown syntax is a bit different, so it does not get converted to HTML. This might have more to do with core, or even using the standard markdown for images with![](https://)
rather than a proprietary one [upl-image-preview url=""]
unless there is a specific reason for that.