Good idea-it is always nice to have the option to carry a little more or redistribute the weight. If you go mostly CC/ warmshowers, and camp only on rare occasions you can get away with a pretty light load. If you primarily camp, cook, want the luxury of a tent, and tour in the shoulder seasons when a variety of clothes, and warmer (bulkier) bag are needed; the option for greater capacity is really convenient.

I have a cyclo- cross bike set up for touring. It is a good compromise between durability, weight and load carrying capacity. While not near as light as my road bike, it will handle wider tires, is sturdy and relatively fast when not loaded. I just put a new fork on it that has mid fork baze-ons. My 2007 model pictured above did not have them, but the 2014 models do. However, the braze-ons were just a bonus. I bought the new fork to get a longer steerer tube so I could dial in the fit better.