I think you can commute just fine on either of the bikes you're looking at.

I occassionally commute on a CF racing bike and don't see the need for anything else.

Dedicated commuter bike can allow you do some things with it, that you might not want on your road bike, such as fenders, racks, mounting lights, wider more flat resistant tires. But for most people's commute, there's no need for a seperate commuter bike.