Do I need this? No, you do not but it's very helpful. 

When it comes to adjusting the EZ-Levels... any inexpensive low voltage handheld driver is by far the best tool for the job!

Drills... work fine, but they have way too much torque, so you have to be careful. 

This electric driver allows you to raise cabinets up quickly without the extra torque.

I use one on just about every job.