Super well insulated latent heat thermal storage batteries will have lost all the stored energy after roughly 3 months. And I can't think of no more stupid way to charge them than with electricity. So no, this is just another WEF pacification hype.

Latent heat storage is fine for day-to -night and occasionally to bridge 2-3 day cloudy period. But that's about it. And if you are going to do it, then do it smarter. Burry the tank underground (less thermal gradient) and use higher density materials than sand, like metal slugs or use change phase materials (expensive).

For loss-free seasonal storage of thermal energy, you would have to look at chemical conversion solutions, like salt batteries. But these still have high conversion losses in the order of 25% (heat) whilst charging and 25% (cooling) when unloading. Fine if you have a direct use for those losses. But it does mean that you must double your collector surface or use waste heat.

As a collector, the efficiency of thermal collectors like vacuum tubes are in the range of 95% instead of 20-25% for PV. So that's a no-brainer.

But the question not asked...why. Because with a normal water-to-water heat pump you can achieve the same or even higher efficiencies at lower costs and much less space used.

For those living in moderate temperature zones...watch the development of ultra-high vacuum flat panel collectors closely...