The concept is pretty nice if you have a problem with one deck when you arrive at the club.
In Torq this was implemented as amputate mode. You would basically have one deck on time code, and then 'clone' it to the second deck where it continues to play at the same speed.
The turntable then gets used for cueing in the next song. It's sort of like an assembly line and you 'push' the tracks down to the software controlled deck as you work through your performance for the night.
It also allows you to move into time code more easily as well since you only have to buy one deck at a time.

The process has saved me more than once when I had a problem with one turntable at the club or something crazy happened (like RCA's on the turntable getting caught in a flight case lid and being cut).