(pref sea water)
doesn't matter because you have to purify it anyway
direct hydrogen uses that make sense given hydrogen is cheap are ammonia, methanol (also from biomass), steel and generally speaking fine chemicals. methanol and ammonia can be used as fuels for cases where BEVs don't work, like shipping. this also requires monstrous overbuild of power grid
prerequisite for cheap hydrogen (cheap electricity) will also make further electrification make sense and that eats lunch of hydrogen use for power even before hydrogen infra buildout happens
"individual researchers with bold ideas" will mysteriously turn out to be republican techbros