If one runs out of battery, malfunctions or gets lost, then you will have the other one at hand.
I typically take 3 or more cameras on a trip. You are going on a very scenic trip and your cameras are quite light weight and very portable, why not take them both?
I'm going to Utah, Bryce Canyon and Zion National Park. I have a Canon G9 which I love, but I only use the Automatic functions. I also have a smaller Fuji finepix F70 EXR which I got last Christmas.
Anyone with the Fuji or Canon G9 have any preferences?