The concept of using waste heat from some useful process (eg. running a CPU) in place of pure ohmic heating as in an electric bar fire, is a good one. The total amount of heat produced from running a 500W computer is, as anyone with a basic understanding of physics knows, exactly the same as a 500W ohmic heater - so to convert electrical power straight into heat without it doing something else useful in the process is always missing out on an opportunity to get something for nothing. (Not energy, of course, but 'usefulness').
It's a shame this is so poorly understood, by the people who propose these schemes and those who back them. The lack of elementary knowledge about heat, temperature and energy here is staggering, and the fact that they'd announce it so clearly in public, embarrassing.
I had an idea years ago to use the waste heat from a desktop CPU to brew coffee. If a CPU draws 100W and can run with a water cooling system at, say, 90 deg C, then there should be enough heat available (and at a high enough temperature) to heat water for coffee via a heat exchanger. The whole lot could be built into the PC case, and would be the first genuinely fit-for-purpose "developer's" PC ever made, IMHO.