At that point, just use battery storage and bypass the reactor entirely.

For domestic day-to-day consumption, absolutely.

The main argument for hydrogen AFAICT is that it can be exported overseas or stored for inter-seasonal use.

Batteries can't do that, as 1) when compared to literal rocket fuel, they're impractically heavy to put on a cargo ship for bulk transport, and 2) batteries trickle-discharge so after a month or two the battery will be flat.

In fairness, pure hydrogen is also leaky and hard to work with. That’s why I was asking about the economics of turning it into methane… and yet, one of the other replies I got pointed out that methane is also a bit leaky, so we might want to reform it (or whatever the word for “opposite of cracking” is) all the way up to a room temperature liquid.

I barely remember the process from school, something like this rings a bell: https://en.wikipedia.org/wiki/Catalytic_reforming

The largest energy draw is making the hydrogen. Store that and operate the reactor 24/7.