"stable" currency isn't "stable" because it doesn't exist in a vacuum. Populations grow, economies expand, efficiency increases. If I have $1 in 1919 when the GDP was $500B (and there were only 100M people) vs $16T (nominal), and I sock it in a drawer, I now own a much, much larger share of the US money economy than I did. I didn't earn it, I just held onto it. I accumulated value by virtue of "I got there first, sucks to be you."

There's no good reason to encourage value generation through inaction. That's one of the many good reasons to have abandoned deflationary currencies.

If you held a Scottish pound, you typically held a piece of paper from the bank that you got in return for making a deposit.

From the banks point of view, funds in checking accounts and funds issued as cash were pretty much the same. Just that the cash didn't pay interest, and you didn't know who had it. And it could get lost and never come back to you. (Though perhaps similar to people abandoning accounts sometimes?)

Holding the notes issued by a bank was equivalent to giving the bank a no interest loan. The bank itself invested the funds in loans to other companies. You forewent consumption and took on some risk.

Nominal GDP was remarkably stable over that time in Scotland. In reverse that means that one pound represented about the same share of total economic activity year after year. (The absolute, real amount of economic activity increased a lot.)

That's really cool, actually, I'll have to read more into it. Cheers, thanks for sharing.