For example - if a new application version is released there may be very minor differences in the form fields - would be good to do a re-recording and quickly compare with a previous recording and see the differences highlighted
You can't compare at once the requests or responses from two different recordings but you can do it individually request per request.
To do so select one request from your first recording and select the second request from your second recording while holding the shift key. Your two requests should be highlighted and then right mouse click to see a new menu to compare the recorded requests or responses.
Of course that functionnality applies on any requests.