Problem/Motivation
Content creators want their Drupal authoring experience to be intuitive and forgiving -- and linking to Media/files in CKEditor challenges this, because files have to be added to the Media Library before you can link to them. Most commonly, people think about uploading a file at the point of need, not several steps ahead ("I'm making a link to this file, therefore I need to upload it now"). If you're working in CKEditor, adding a file to the Media Library takes you out of the authoring environment and requires a big context switch when the goal is simply to link to a file.
Steps to reproduce
Authors working in CKEditor who need to link to a new file, currently, must leave the editor (remember to save it first!), navigate to the Media Library, add the new file, return to editing the original content page, and insert the link.
Proposed resolution
Enhance the usability of the new Insert Link feature by adding a button or a link in the dialog, that provides the ability to upload a new Media item without leaving CKEditor.
One answer to this issue in contrib is Linkit Media Library. It provides a Media Library button in the Insert Link dialog. It brings up the full Media Library for selection, but, crucially, it has a field to upload a new Media item.
I'm indifferent on whether the full Media Library needs to be available to browse via the Insert Link dialog. The important thing is to be able to get a file into the Media Library without having to leave CKEditor.