If this is going to be your ONLY bike, I would suggest not discounting utility of being able to carry things. Racing bikes (like the caad10 5) are really meant for racing. I would just make two points to consider: (1) For most people (who aren't serious about racing), a racing bike is not useful or needed. (2) The weight savings of carbon fiber or other high end materials and components are irrelevant for the average person. If you buy a bike that has the option of attaching fenders and racks, you can always take them off and still ride fast if you want (not serious racing fast, but fast enough for most people). A steel frame touring-type bike with tiagra components may weight a few pounds more than a carbon fiber bike with higher end components. That weight difference is important for serious racing, but it doesn't really matter if you are commuting at 15 mph. The extra weight provides utility, and I wouldn't discount the value of that. If you buy a racing bike and decide you need to carry something (food, clothes, laptop computer, etc.), then usually your only option is to strap on a hot and uncomfortable backpack. I've commuted thousands of miles with a backpack and also with panniers. Panniers win hands down.

If you want to commute and train for racing at the same time, then that is a different story.