We're traveling in Europe right now and have an iPhone 6s and an Olympus mirrorless camera with a high quality lens. The Olympus takes very nice pictures, but I find that I prefer not to take it and use the iPhone instead. We'll see how the next few weeks go, but at this rate, I might get rid of the camera and stick with the iPhone. Pictures might not be as good, but probably more than sufficient for our needs.
As an added bonus, we get GPS data embedded into the pictures. I should also upgrade iPhone storage to allow backing up of pictures to iCloud. I tried backing up with Google Photos, but couldn't get it to work. Maybe I'll need to try that again.
Thankfully Apple invests in camera technology. Each generation of the iPhone takes better pictures. That alone might be enough reason to upgrade to the latest iPhone.
I'll also add that using a phone as a camera also makes it easy to share pictures with family and friends while traveling. Another plus for using an iPhone.
I wrote more than I expected. Mostly to convince myself that the phone's camera is good enough.