One of the biggest advantages of using thermopower generators will be the fact that power is available where it is needed, not via the grid. In fact, while the grid will still be around even with widespread use of thermopower generators, it will be the backup source for power.
It turns out that the grid is extremely vulnerable to major geomagnetic storms, storms which have occured every few decades in fact. A NASA article entitled Severe Space Weather makes it clear that we could experience weeks of electrical outages if we experience a large storm:
Power grids may be more vulnerable than ever. The problem is interconnectedness. In recent years, utilities have joined grids together to allow long-distance transmission of low-cost power to areas of sudden demand. On a hot summer day in California, for instance, people in Los Angeles might be running their air conditioners on power routed from Oregon. It makes economic sense—but not necessarily geomagnetic sense. Interconnectedness makes the system susceptible to wide-ranging "cascade failures."
By installing thermopower generators on virtually all devices which need power, our electronic civilization will bypass the problem, making us safe and secure from these killer storms.