wrote

Now that I see all of this, I wonder if perhaps in the long term, AGM
batteries are really about the same cost as the more dangerous and
unreliable flooded batteries.

You may disagree.

The electrical system specialists who did the final design and engineering
for my 81 foot research vessel do agree and said pretty much just what you
did. They do both land based emergency power systems for things like phone
company switching centers and sophisticated vessel systems. Pretty
knowledgeable guys.

According to them, you didn't even need to factor in the safety of AGM's to
justify their use.

--
Roger Long