macOS, Use fn + Command keyboard shortcuts work
Even with both  Backspace ⌫  &amp; Delete ⌦ keys,  Cmd ⌘  Delete ⌦  does not clear the line forward of the cursor, even though  Cmd ⌘   Backspace ⌫   clears it rearward.
It would appear the inconsistency isn't in the  Fn   key itself, but in the OS's usage of  Cmd ⌘   Delete ⌦ .
 Opt ⌥  Delete ⌦  deletes one word forward of the cursor, as does  Fn   Cmd ⌘   Backspace ⌫ .