I am one of those rare soles who changes tuning on their floyd equipped guitar a lot.
Since I purchased the guitar in 2014, I don't think I have kept a tuning consistent for more than three sets of strings.
BEFORE I purchased the Key, intonation was rather annoying to set up. You need to block off the trem and take off all the string tension before you open the saddle, then tune up, check and repeat until you are in the clear.
The key makes it so much easier. Sure, you still need to drop the tension when you insert the key, but once in and back up to tension you can keep the floyd floating, open the saddle, adjust, check, adjust etc until intonated. The trem stays floating, the tension stays.
Repeat for all the strings and you are done.
I would estimate it easily shaves a quarter to half of the time needed.
If forced for a NEGATIVE: No instructions in the pack. I had to watch a couple of videos to check I understood how to use the device correctly. (Ahem, I actually prefer this, as it produces less waste - I did say if I was *forced* for a negative =) )