When the master file that has a linked component is deleted/moved the component cannot be made local. So if you have a corrupt file, that you are able to copy and paste to a new document (Adobe suggested debug/fix) and you delete the corrupt file, the component is left a component with a broken link.

"Unlinking" the component turns it into a group. So if you used that component on multiple art boards you have to replace them all (no easy way to do that...). If you go into the assets panel and click the dropdown and "x" out the linked document, they all turn back into groups.

It would be great if turn "to local component" option was always available even if the master document was removed.

Better management of linked components, linked files and swapping of assets would be a vast improvement to managing large systems.