When do you use an ADAT?

[HFR]

I have an analog mixer connected to Line In of my computer and I am just starting to use Nuendo 1.5, so how would a ADAT apply to my setup? I have already recorded directly to my computer so why would I use an ADAT?
thanks.

 

[Track Rat]

You wouldn't. But you do need some way of archiving your work. Personally, I back up to CD-R.