> Real-estate on the Moon is also divisible and un-manufacturable, but no-one seems to be arguing that we should base a monetary system on _that_.

From the perspective of a fiat currency serving as a store of value, Moon real estate is a great idea. The exact amount and location of it is available to anyone in the world; it's tamper-proof; and unlike regular paper money, it's difficult for it to be inflated.

A currency with zero nominal inflation translates to effective deflation in a growing economy. If you own x% of the moon, and no more moon can be printed, you'll hold your lunar notes under a mattress waiting for their value to rise and nothing productive will ever get financing.

I'd rather have a little ongoing deflation than risk becoming the next Weimar. Or China(s). Or Turkey. Or Yugoslavia. Or Zimbabwe...

And inflation imposes costs of its own just from adjustment and uneven inflation discourages investment on its own (holding debt comes to mind).

I think you're the first person to think of it. Good idea. I will be arguing for it from now on, because not only is it divisible and un-manufacturable, it wouldn't inhibit industrial uses of gold or anything else.