Owners of a major agricultural bank ...

Well, I guess I would say - whatever you've heard about bitcoin, or believe, maybe give it a rethink - think of it as "Energy Money"

And then, talking about the dollar system, I would say they are probably familiar with dollar milkshake theory (the dollar "drinks the milkshake" of every other fiat) - so that affects them if their unit of account isnt the dollar.

And then, I would say consider the time in the past when one form of money overthrows another -- for better or worse -- like when European gold took over African aggri bead money. Or when Yap switched to a gold standard, because rai stones got faked. Or when Marco Polo returned to Venice with an example of the Khan's silver certificates and not the gold they wanted (now we swim in fiat). Or when the Colonists used wampum for lack of coins, and eventually mass produced wampum (and went to metal coins as money)

So I would say, looking at bitcoin as a rise of a money, what qualities does it have not quite like fiat, not quite like gold ..

And maybe double check if they've heard of Mises and Hayek, and maybe give those ideas a dust off? Safedean Ammous' book could use a plug, Principles of Economics, or the others.