Eregulla Deeps, page-93

One more problem - hydrogen gas is a huge pain in the a*se.

It weighs nothing, it leaks out of everything, it's almost impossible to liquify (so transport extremely difficult and expensive), the stoichiometric window is enormous (it always wants to kill you), it causes metal embrittlement (leading to sudden and unexpected failures), and if you're extracting it from natural gas why not just burn the gas?

It probably strips out lubricants and needs to burn oil like a 2-stroke too.

Terrible fuel.
Terribly inefficient method of chemical energy storage.
It's an expensive, dangerous, and inconvenient battery.