Elaborate. How are we making H2 from sunlight? Electrolysis from solar PV? There isn't enough. Why waste 10kWh of electricity from solar to make displace 4kWh of fools fuel with H2 when we can use the same 10kWh to displace 8kWh of fools fuel with a BEV?
'Inefficient' Solar panels make sense because we're starting with more sunlight than we can possibly use and it's free. Similarly H2 as an automotive fuel won't make sense until the same can be said of electricity from solar or wind.... we need to have more of it than we can possibly use and it needs to be ~free.
I totally agree that if we get to the point that we're flooded with an excess of energy from solar and wind, we have nothing better to do with it than split water AND all the things we need H2 for are satisfied using surplus H2 to power cars will make sense. That's at least ~50 years away. But at that point we could probably just start sticking Cs from atmospheric CO2 back onto the Hs and make C8H18....
Electrolysis is how we do it now though projects are underway to do it directly from sunlight. The answer to "There isn't enough." is that we have to build more until there is enough, as we are doing ever more efficiently and economically as we continuously improve the technology and processes.
The fact is that currently there are times when we produce so much surplus electricity from wind and solar that producers actually pay to dispose of it.
You have the same issue with renewables as you do with conventional, that you first have to build enough capacity, with reserves for all of your needs, including downtimes for maintenance and failures. With renewables, due to intermittence when the sun isn't shining or the wind isn't blowing it just needs to be larger to account for whatever inefficiencies result from having to store power for those periods.
The only criteria is that you are able to do that economically, not how much of it you lose as waste along the way. Of course reducing inefficiencies and waste where you can helps with that, and doing so is a competitive advantage for one method over another. Once again though, whatever the intermediates, only the overall economics can ever ultimately matter.
Stationary onsite storage offers more options but those do include the two we have been discussing, batteries and hydrogen. For vehicles, battery power must be transmitted over the grid with its inherent losses and waste heat production, then batteries must be charged with that loss and the waste heat produced by both charging and discharging of batteries.
Hydrogen however can be produced for vehicle fuel either onsite and in conjunction with stationary use and then transported, or at distributed locations drawing power from the electrical grid. In either case that production can be easily managed to balance production and demand on the power grid, which would be a far far more complex and challenging task to do with many millions of batteries charging at consumer discretion.
There are also multiple ways to store and transport hydrogen, not just as a compressed gas, and as a gas it can be distributed both in tanks and via pipelines.
Do not misunderstand me. I am not advocating for hydrogen. I am challenging the claim we can't manage the physics to make it a competitive and viable alternative.
