If you look at the Dialer permissions, there are quite a few things it's involved with, so it stands to reason it may show up under battery use depending on various factors and what apps are used. I've noticed it may be the stock message app (for texts) that seems to trigger the dialer showing up under my battery use (although it never appears to cause any battery drain). I can make and receive numerous phone calls and the dialer is never listed. But as soon as I open/close that stock message app, later I'll see the dialer listed in single digit use. I rarely use text messaging, so I wonder if the dialer issue is more prevalent for those who frequently text...