I'd be very surprised if hydrogen vehicles work out. Hydrogen is not a source but rather a store of energy like a battery is. There's a few practical and technical issues:

1 it would require building out entirely new infrastructure, running up against severe NIMBYism at this point. It's incredibly hard to even build new power lines right now. Try a highly combustible, very leaky gas.

2 it's far cheaper to just strip H2 from natural gas, which releases carbon (unless you capture it, increasing cost), so not carbon free unless you force using electrolysis from renewable power sources

3 Electrolysis efficiency is ~70%, fuel cell efficiency is ~60%, so round trip efficiency is <50%. Much more waste than a battery (~80%). You're both using essentially the same electricity to create the power, but hydrogen is wasting more of it, so will necessarily be more expensive

4 in vehicles, fuel cells end up charging the battery toi power the motor anyway, so the energy loss from the battery is a wash

The one thing they have is range and speed to refuel, but as batteries get cheaper and better that will be minimized before H2 gets big enough to take over.

There's lots of big companies with smart people who are still pushing for this so hopefully they know what they are doing (mostly in Japan it seems)

Possibly a bit off topic,but why do we charge the batteries at stations rather than switching them with full ones?

probably because we park our cars, instead of giving them away when we reach our destination, and getting one when we need to go again.

Have we figured out a good way to store Hydrogen that avoids leakage? I've heard that even thick-walled stainless steel vessels can leak ~1% a day.

Yeah, you coat the cell interior with platinum. Adds significantly to the cost and complexity of production though.

and use platinum in the fuel cells. the real-world problems are pretty obvious though - Pt is worth stealing and it's expensive 'cause there aint that much of it so you can't expect to use 100x as much as now and not expect the price to change. FC's are niche. Batteries won.