RE;
Hydrogen in order to be usable to deliver needs to either be pressurized of "pulled" in by forming a vacuum.
Pressurizing hydrogen is tricky and not something I really wanted to try, except in very small amounts.
It will take a whole bunch of it either stored at very high pressure (3000psi) to have enough to be able to do a lot with it. otherwise you're going to need some weather balloon sized balloons to hold any.
Propane/Methane can be made liquid much easier, the chicken poop guy actually bubbled his methane through water then pressurized it using a diver's pump.
The available energy to make use of is another factor. Not looking up any math or googling . I think stored H2 has 1/6th the available energy as stored propane/NG.
Hydrogen with its flame spread and extra hot burn properties is one of the better reason why its so good as an on-demand fuel. It can be made and fed up-stream in the air/fuel mixture, this helps the flame burn hotter, making a more complete burn for the gas which in essence makes more power available and less fuel needed for the power needed , thus giving better fuel ranges.
Hydrogen and even Alky (E100) items used to be almost not allowed on this forum. This was due in part to people spouting un-supportable claims.
Before I started posting methods and uses of Alky for fuels, I made sure it was okay with the Admins and editors.
I my opinion: They began allowing these posts once real-world users, maker's where posting.
I try not to post about something I haven't at least tried or are doing and the Admins have been very nice to let me pass-on what I've done/learned.
For uses and builds you might have a look at Tecker's posts and I think he has a web with these as well. He's 1 who's done it doing it now poster(s).
Hope this helps;
Ask anytime;
Cheers
Bruce S