Most of all it's an intermediate for even neater chemical storage mediums. The entire range of non-biological regenerative fuels (or non-biological, period, if

Most of all it's an intermediate for even neater chemical storage mediums. The entire range of non-biological regenerative fuels (or non-biological, period, if we include fossils in the biological group), including reduced Fe dust cycles, ammonia or plain old "e-fuel" hydrocarbons, they all start with hydrogen as the first stage. It's the natural short term storage medium that will be used as an input buffer for downstream processes so that they don't have to follow supply peaks as closely as they would have to without that buffer.