If I have understood it correctly, the same nuclear power source also maintains workable environmental conditions for the instruments on the rover irrespective of harse climatic fluctuations on Mars...continuously. Hence, it is required to avoid unnecessary power wastage in order to maintain power for the mission time (2 years??)...my two cents.
No doubt there's a PR angle to Curiosity's "dream mode" since the technology itself isn't really pushing the envelope. What is, of course, is the application: an autonomous vehicle monitoring its own systems from an average distance of about 140 million miles.
In reality we have been making products with this type of functionality for years. Most set-top boxes we make use a micro-controller for external interfacing and sensing. They perform a power management function, receive remote IR commands and schedule wake-ups. I credit them with a success because the NASA approach is much more expensive but much more powerful, I imagine their FPGA based design is able to monitor the fine data from a wide range of sensors and make decisions, rather than our simple listen and wake logic.
I think that using a FPGA to provide basic instinct and reactions to save power is a great idea! Not a new one, I have been doing that for years when I was driving home from yet another late night when I had 1.5hr commute times (kidding really!)... I do like the idea of a smaller processor playing baby sitter so the mom/dad can nap..
Especially the so called "dream mode". I expect this term attracts the marketing gurus associated with general purpose microcontrollers and microprocessors. Then the new ad will say "The lowest power dream mode microcontroller in the world...".
It is a great piece of Engineering Design that has started successfully walking on a no man's land. Lets see for how much time it is being able to roam over the red planet. It is tough to predict that How much the information obtained from Mars will be useful to mankind but the Dream Mode and the Robot design will surely help the Automobile industries on technical fronts.
Speaking of heating, JPL reports that temperatures at Gale Crater are greater than their models predicted, and therefore so is Curiosity. Temps will undoubtedly drop when the rover starts climbing the sides of the 18,000-foot central peak, Mount Sharp. The plutonium power source should make continuous operation much easier than the solar-power Opportunity and Spirit rovers.