I wonder if thermal storage as a battery is more useful in space without an atmosphere to worry about. In general I wonder what kinds of processes are easier when everything is in a vacuum.
Dissipating heat in a vacuum is certainly more difficult, since it must all be done through radiation instead of convection. It follows that thermal storage would then be more efficient in a vacuum too. I couldn't say whether it would be "better enough" to make it a much more compelling option than it is on Earth though.