It's posited as a "dump" for excess electricity; while batteries may be good for storage and balancing out the grid, hydrogen is suitable to put everything else in, that is, what if the batteries are full, or there's still more electricity in the grid that has nowhere to go? Hydrogen generation - as far as I'm aware - can scale to schlurp up any excess to a huge amount in the same plant.

The other one - in my country - is that they want to wind down natural gas entirely, but then want to reuse the pipes for hydrogen; I suspect this may be to continue making use of the huge infrastructure investments made in the gas pipelines.