Feature request:

What steps will reproduce the problem?
(1) Preview a file in Quick view (from Files app)
(2) Press Alt+Delete

What is the expected result?
A popup is shown to confirm deleting the file.

What happens instead?
Nothing, file deletion is not allowed from Quick view. 

A good example of when this would be useful is going through multiple similar photos to choose which one to keep. It breaks the flow to have to exit out of quick view to delete and then return back.