I voted "Yes"; however, there is a caveat.
It is not that I find myself using my 5D3 less, it is that I find myself taking more photos because I have the iPhone 5s with me at all times, most significantly times when I would never have had my camera with me in any event (business trips, simply out shopping, etc.)
The person who's signature says the best camera is the one you have with you is quite correct. The iPhone may suck as a camera, but it beats having no camera at all... (it does, however, make a superb copy machine for things like business cards, prescription bottle labels, and directory listings, none of which the 5D3 would be very useful for, since you'd never had the camera when you need to look up the info in the image)