One reason for my skepticism is that I've been hearing optimistic predictions around hydrogen as an energy store for decades at this stage (I'm old) and for a long time believed them but here we are, with little to show for it. In fact, at historical scales, hydrogen's significance as an energy store today is less than it was in the 19th century. As a result, I've adopted "I'll believe it when I see it" approach so I just ignore hydrogen predictions - particularly ones 25 years into the future.
But the main reason is simple physics. It simply has NONE of the physical attributes you'd want in a gas to be used to store energy. It's like if you picked all the attributes you WOULDN'T want in such a gas.
Storage and transport are incredibly expensive and technically difficult. Everything it comes into contact with needs special materials to avoid embrittlement. It's prone to leakage.
It has dreadful energy density. The worst.
It has potent green house gas effects when leaked into the atmosphere.
It's dangerous and highly explosive and burns with such high intensity (and invisibly) that it requires specialist fire-fighting equipment.
Roundtrip efficiency (electricity to H to electricity) is abysmal - a fraction of that of batteries.
In summary, hydrogen as energy store makes no sense to me. And it's completely hypothetical. If we are going to talk about hypothetical approaches to storing energy in the form of a gas, then green methane makes a lot more sense. Not that I'd advocate for either but I see some potential for green methane but none for hydrogen given its physical attributes.