This is true —- but the total quantity of battery storage potential is utterly dwarfed by the storage potential for gas, in subsurface storage reservoirs and salt caverns. You can store days worth of energy in batteries; you can store a winter’s worth of energy in gas.
It’s not a matter of efficiency, it’s a matter of quantity. We do not, and will not, for decades, have the kind of battery storage required to support the grid.
Hydrogen's atoms are so small they try to pass through the crystalline lattice of metals, making the hydrogen-enriched layer which is more fragile [1]. Your regular polymer hoses are much more permeable to hydrogen.
Hydrogen gas burns with entirely infrared flame, not visible to human eyes [2].
Hydrogen, even highly compressed, is still very lightweight, so storing significant amounts requires either very high pressures, or liquefaction. Liquid hydrogen requires an uncomfortably low temperature of 20K, but starts to freeze into solid state at 14K.
Hydrogen is the most efficient rocket fuel, there's no denying. For all other fuel applications, it's pretty problematic.
Also, there are ways of storing hydrogen in metal hydrides at room temperature and pressure. This makes a LOT of sense for people who may want to have an option of buying stored energy - such as those who live in apartments without access to the terraces where solar panels can be deployed.
If these metal hydride storage is used similar to how changeable batteries are used, it is conceivable that you could drive up to a place like a fuel station just to change out your metal hydride storage in a matter of a couple of minutes and perhaps even get additional supplementary units packed at the back of the vehicle if they intend to go on a long journey.
https://www.frontiersin.org/articles/10.3389/fenrg.2021.6161...
In terms of cost, it is also now possible to use Boron Nitride for storing hydrogen - very cheaply and very safely.
https://www.geelongmanufacturingcouncil.com.au/2022/07/innov...
Less storage problems, more options (higly compressable gas, or pure liquid, or "liquor" (dissolved)), and no mucking about with fuel cells.
Just straight up movement of energy (with losses to be sure) from places with an excess of sunlight to those that are short.
Fun observation: If some of the hydrocarbons created this way make it into plastics that isn't passed back into incineration (or a better form of recycling) you'll have true carbon-capture for the fraction of the carbon that came from biomass. Without we trying.
