You shouldn't ever need to know it, there are other ways to do everything I can think of.
What problem are you having that you need it for? Maybe I can tell you how to get around it....
My computer is backed up via TSM to my university's central ADSM server. If I want to do anything which needs more than my own node password (which I know), I have to raise a support request with them. For password resets, these are set to something random which is then sent out on paper arriving a day or two later! Therefore, if I want to be able to recover files in the event of my machine dying (as I did this afternoon), it's invaluable to have the node password so that I can use the -virtualnodename option on another machine to get back my files more quickly and get back to work.
Similarly, if a machine dies completely, one also has to wait for the paper password to arrive before being able to get on with doing a bare metal restore because of course the encrypted password dies with the machine. Hmm...
Why has this facility (or the MAILPROG equivalent) been removed from v5.3 and upwards? This seems a useful sort of thing to me.
Thanks,
Chris.