Normal behavior of clipboard handling (Copy/Cut & Paste), is that the content of the clipboard replaces the selected items. E.g: Copy a piece of text (to the clipboard), select another piece of text, choose Paste, and the selection is replaced by the contents of the clipboard.
But, unfortunately, InDesign breaks this rule, when trying to replace the content of an image frame.
It is not able to Copy the content of a frame, and replace the content of an other frame. We first have to remove the old content, and then choose 'Paste Into'. Why not make it intuitive like any other clipboard operation?