The way this hydrogen stuff seems to work best is in a PHEV; in other words, a plug-in prius-like car that runs on hydrogen. It's got a relatively small fuel cell, and you plug it in at night to charge up a small battery that can go a few tens of miles.
Most of the time you run only on the battery; and that's fine for everyday use.
But for long distance, you turn on the fuel cell and it keeps the battery topped up as you drive around. Producing the hydrogen isn't very efficient, but you're only using it for a small percentage of your travel, and you're using spare solar energy that you couldn't otherwise use.
AFAIK the effective energy mass density for hydrogen storage now seems to comfortably exceed lithium ion batteries; so for long distances hydrogen makes sense. Also the embrittlement issue is not a problem if the materials are chosen appropriately.
There's still problems with the lifespan of the fuel cells; but again you'd only be using it as a range-extender, so it's not used a lot. Fuel cells are somewhat expensive for the power they produce, but using them as a range extender, you don't need a huge amount of power, most of that comes from the battery; that greatly reduces costs.
The systems are still expensive, but getting cheaper, and there's infrastructure issues; but they're not as bad as electric cars were, since the filling stations can be further apart, also hydrogen makers for home use are unlikely to be super expensive for slow filling overnight.
Personally I don't like PHEVs much, but the hydrogen PHEVs seem to be borderline doable now, they're actually in production.