Earlier, Infrequentflyer789 mentioned it possibly being beneficial for the automation to "take a break" on occasion.
In my opinion, that would be of very little benefit, if any. As I wrote to ChrisN, the skills required to deal with an abnormal in cruise are far different than the skills required to take over from a lazy autopilot every once in a while. Allowing the automation to take a break would only provide practice in normals; what the AF447 pilots ( and most of the rest of us, including myself) really need is practice in ABnormals.