First, the use of the APC kiosk does not mean you will not see the CBP officer, you will still have to see an officer at a booth, it just saves the time by making the job easier for you and for the officer, basically by making you help the officer in doing some of the job (scanning the passport, taking the photograph, etc.).
Hence, the above made the waiting times shorter since the CBP officers can process more application in less time. From the Atlanta-Hartsfield airport website:
APC is a self-service kiosk that allows passengers to submit their declaration and biographic information electronically and reduce the time they spend with a CBP officer. This has resulted in an average 20-40% decrease in wait times at airports that use APC kiosks.
So, to answer your question, using the APC kiosk will make the whole process easier and shorter, for you and for everyone else.