You'll use Siri. Maybe not every day. Maybe not for everything Siri can do. But Siri does certain tasks so much faster than you can do manually, it's pretty crazy not to use it. If you ever use alarms, or timers, Siri is faster. If you ever check the weather, Siri is faster. If you ever want to make a reminder, especially a complicated one involving repeats, Siri is much faster. If you ever want to check something while you're driving, Siri is safer. With iOS 6, and I've been using it as a developer for some time now, Siri saves a lot of time on a lot of tasks that would otherwise involve lots of typing or settings-fiddling. With one spoken sentence, I can do so many things that might take me a whole minute otherwise. iOS is fast and easy and intuitive, but ultimately it's not as fast as your voice. Heck, just having Siri open apps for me is faster in some cases than trying to remember on which of my many home screens or folders I stashed that little-used app that suddenly is very important.
Siri was a fun novelty at first, but I found my use of it increased over time, not the reverse. With iOS 6, it is so much more powerful.