We can get lost in the details with maths Ian, the most important thing to note is the full spectrum of benefits associated with it. List all the stakeholder concerns including the planet as a key stakeholder, it's a massive list, and convert those to a specification of requirement, a system specification which nothing else can meet. Aerospace is the big one, the bulk physical material associated with batteries kills their application to long haul flight.
Future availability of food and water are also biggies, the fact hydrogen addresses both of those is remarkable, actually in the case of food more like a miracle. Who would ever have guessed we would find a way to convert it to human consumable food?
The fact this incredible possibility exists is like a message from nature, we just know this capability has to become crucial, given we know we are uncontrollably decimating the natural foodchain, we are absolutely going to need something to remove at least part of our load from it, it's like a lifeline sent by nature with a note on it that says "You are gonna need this".
As said the maths and the cost becomes so much less important when we come to the point of crisis, which has to happen if we don't preempt it, will force us into full on non profit mode, relief and stimulus will become de rigeur, we will notice there are ways of aligning it with energy then cost won't matter, and efficiency becomes less important when we realise it just works, it does what we need, and nothing else can do everything it does.