reality: They dont work.
Honda has been trying to make it happen for 20 years now https://en.wikipedia.org/wiki/Honda_FCX its all a huge failure https://www.autoweek.com/news/green-cars/a36751587/honda-cla...
Whats fascinating is the realization Honda toyed with EVs even longer https://en.wikipedia.org/wiki/Honda_EV_Plus and still managed to fail miserably.