This is like the maintenance engineer saying to the pilot of an aircraft, “Don’t worry if the displays give you any of ten thousand critical errors, if the engines light up green, you’ll be right, mate.” !!!
So why is it in Oracle’s code? (Spotted during a trace of an Edition Based Redefinition operation.)

One of many places the AskTOM team say WHEN OTHERS THEN NULL; is almost always a bad idea…
https://www.youtube.com/watch?v=Dw0qRw8P0cQ