Your comments on his reasons are clearly counter-factual:
Load shifting on a consumer scale has been happening for decades in various places around the world (e.g. cheap nuclear energy at night powering storage heaters)
Self-consumption: in a grid increasingly fed by solar power all those peaks hit at the same time and there's been multiple recent news stories about power prices going negative at those peaks.
Backup - no-one said anything about "true" natural disasters. Backup from short power outages is already an established market in many outlying areas and a fringe benefit for almost anyone. And no-one said that you had to buy it and use it for this single purpose.
This whole area has been predicted as a growing market for years, there's others in this thread complaining that it's nothing new compared with less famous competitors, so complaints that it's a product dreamt up to soak up subsidies is a bit odd.
Having said that, if I was in charge of a government, I'd be subsidising these kinds of decentralised grid backup right now as they are already useful when viewed at a national scale. It seems likely that in a few short years they'll make economic sense for more and more people without any subsidy though.