Also when sodium hydroxide reacts with acid it releases CO2 and it affects growth of at least some fungus. Also, if a brick sized fuel cell can provide 1kWh and single transatlantic flight consumes at least 20MWh you’d need a pile big enough to build a house which doesn’t sound feasible.

But I’m not a chemist either, I suppose it boils down to comparing negative effects between this new cell against kerosine. Plus there’s always the case which affects any new kind of storing energy where it’ll be indefinetly ‘ready for market in next 5 years’.