Like you I need to have the real thing close by
#1 reason it's nice to actually have something to show for the $s spent, and #2 the program and serial no's are there in case one has computer crashes, and these things dissappear. It has happened to me, and it's a real pain to have to contact companies to download again, especially if one need passwords.
You can put any program that you have legally purchased onto a thumb drive or a CD, so you have a back up.