Actually having now read a link elsewhere in this discussion (https://www.thedrive.com/tech/26050/exclusive-toyota-hydrogen-boss-explains-how-fuel-cells-can-ach

Actually having now read a link elsewhere in this discussion (https://www.thedrive.com/tech/26050/exclusive-toyota-hydrogen-boss-explains-how-fuel-cells-can-achieve-corolla-costs https://www.thedrive.com/tech/26050/exclusive-toyota-hydroge...)... It seems that _liquid_ hydrogen escapes from small containers fairly quickly (weeks) and requires temperatures close to 0K, so cars use pressurized hydrogen _gas_ (700 bar for the Mirai) which doesn't escape. _Mass_ storage of liquid hydrogen is no problem (months).