Yep it was there since N3 
Hehe, BigK, thanks for the good laugh!
Well:
Probably most often when I’ve been coaching a singer in-between takes, especially when it’s a line that they’re having a hard time getting the interpretation right on. There comes that point when they finally get it right while rehearsing it acappella, and I say “You got it!” and then play it back for them even though I wasn’t supposedly recording. Being able to hear themselves singing the line properly really helps them get it into their head. Also there have been times when that line became the one that I then dropped into the song. Ditto for instrumentalists rehearsing their parts in between takes. Also there have been many times when an artist has decided to improvise along with a song when were just having a listen back, and I was able to capture something magical because I hit record after I heard them start. Lastly, it has happened when I thought I had engaged record during a take and then noticed that the machine wasn’t recording, and so hitting record 10 seconds late was no problem at all
I can second that 1/1! All situations!!
Though I have only 2 sec of pre-rec… When doing these vox-training stuff I usually just solo the track by hitting S and then recording - just doing this by default when I feel this could be usefull…
But these 2 sec are enabling me to catch a manual drop in even when beeing distracted by typing an SMS or something 
Usually I catch it but it CAN happen that the 2 sec prerec is usefull here
Yes, sometimes I wish that I have set to 40 sec pre-rec or something … when something funny happened and when you hit rec the beginning is still missing… But I am recording that much, I would get lost in Terrabytes of useless data…