That's a hell of a "Other than" you have there.

Long fill times? This commercially available one says 48 hours to re-charge it.

https://www.fuelcellstore.com/hydrogen-equipment/hydrogen-st...

Yeah, but ideally they'd be swappable. Similar to propane tank exchanges. Or even how some EVs were thinking about battery swap stations.

Ehh, I feel like there's some challenges there.

In the Toyota Mirai, for example, the tank is located under the passenger's seats, in a nice little 'braced' area. Likely chosen because it's the least likely location for the tank to get damaged in a collision. Also the challenge of either having to 'choose' between a 'swap' tank and a 'fill' tank, or a more complex tank that does both.

The tank I linked to says it stores at 400psi, and the material data sheet indicates it doesn't vent the hydrogen in a way that creates a significant fire hazard. So I don't think these need the same kind of protection as a high-psi tank. Though I'm sure there are challenges, or we would have heard about them being proposed.

Aren't they really heavy? This is also why swappable batteries in EVs never got off of the ground. You need a crane to do it and that's too much effort for a top-up.

I thought the tanks were much lighter than the batteries. I think they use multiple smaller tanks due to the rate of release of the hydrogen.

I don't know. I haven't done a lot of research since it will be at least another decade until a decent vehicle suiting my criteria comes out (electric or hydrogen). No point in me even looking at it now.