I haven't familiarised myself with the latest in hydrogen development, but isn't the round trip efficiency absolutely horrible? Not to mention boil off and leakage (afaik no material exists that can store hydrogen without leaking).
Hydrogen as energy storage would be amazing, but as far as I am aware it is still far from practical at this point.
Efficiency only matters in so far as it affects cost per MWh. It is plausible (from what I heard at least) that hydrogen is cheaper at the required scale than batteries. After all we will likely have incredible oversupply during long summer days where electricity is essentially free. Scaling battery manufacturing to store enough power for a whole winter is difficult.
In any case I think storage is something where „let the market figure it out“ is a reasonable strategy.
Round-trip efficiency is not the only variable at play here. Storage plant longevity, self-discharge over very long periods of time, cost of installation and maintenance, cost to the environment to source the raw materials etc also play a big role.
Round trip efficiency might be way less than any other method of storage, but it might win out on all the other points. I don't know the answer though - just saying it's important in discussions like these to not get hung up on single metrics. We're not playing trump cards.
Hydrogen as energy storage would be amazing, but as far as I am aware it is still far from practical at this point.