Digital photography

Unless you shoot every 5 minutes, it doesn't eat the battery, especially when you put it on airplane mode.

Touring is possibly one of the most likely situations in which even the most un-racer Grant Petersen worshipper would actually like to map their ride. And have a working phone for emergencies (there may come a time when you're injured, alone, need to make a call and don't actually have the faculties or time to fuck around in your iPhone settings).

Biggest advantage is being able to edit on the spot/later in the evening, a phone screen have a high enough resolution to see whether the photo you took is decent or not (easier to spot camera shake).

If you're editing pictures on the road (after each day's touring), and you really actually like taking pictures, and iPad Mini + SD card reader or MacBook Air isn't too much to take with you and will be far easier on your eyes than fucking about on an iPhone (not to mention how difficult it is to transfer images off an iPhone without an internet connection). Oh, and then there's the storage issue.
An added bonus of having a separate camera is that you can (just about) afford to drop it, get it wet, or lose it. I'm not a fan of putting everything into one device, mainly for that reason.