Hydrogen has other uses too. Currently we use gas which results in carbon emissions. But with cheap enough energy, you can get hydrogen from water. There is also an option to not emit the carbon when using gas, but you get less hydrogen for the same input so no one is going to do that at scale.

Another major use for hydrogen is the haber-bosch process.

That's why it will never IMO be feasible until we have surplus electric power that it can be made with. Power that would otherwise be wasted.

Yes, but it can be stored where batteries lose power over time. And a lot of the infrastructure doesn't need to be build but can be converted from natural gas use.

In the end batteries and hydrogen fill two very different gaps. You can use batteries to shift the renewable production peak at noon (thanks solar) to the demand peak in the evening, maybe even flatten fluctuation (in production and demand) over a few days. But they are entirely useless as seasonal long-term storage.

Also plans to produce green hydrogen exist independently. It's a requirement to decarbonise a lot of industry processes where direct use of electricity doesn't work. It's also a raw material in chemical industry.

So if decarbonisation of more than just electricity production is the goal, large scale hydrogen production is a given. As is large scale storage as production from renewable energy will always have seasonal fluctuations. From there having it also double as long-term on-demand stored energy means just scaling up what is already there.