View the original community article here
Last tested: Sep 18, 2019
The tile becomes a Look-less (i.e. Explore-based) tile! You will lose the dropdown option of "View Original Look", but it shouldn't break the tile/display errors/not work. Everything should continue to function as expected! So if an Admin wants to clean up Looks that aren't used but utilized in dashboards, they can totally move them to the Trash folder.