I got the answer for all, but Interactive from here.
But what does Interactive do?
(anyone from Windows, suspend = sleep)
The "Interactive" option should show a prompt with multiple power button press options.
In other words after pressing the power button a pop-up dialogue should appear containing separate buttons for Shutdown/Logout/Suspend/Hibernate allowing the user to select any one of them and then the computer will perform the chosen action.
But the catch is the "Interactive" option doesn't work as expected in newer versions of GNOME shell (most probably v3.18 and later). So most probably your computer would just suspend after power-button-press without showing any prompt.
Not sure whether it's an intended feature or a bug, this bug report is marked as "resolved fixed" without actually fixing the issue.