Why very small payments are hard: "it's important to distinguish between technological and mental transaction costs", and the latter are usually more important. https://archive.is/fzL0I http://nakamotoinstitute.org/static/docs/micropayments-and-mental-transaction-costs.pdf … …
The equivalent is a compelling counterpoint to my thesis that ocean cities will have efficient govts, due to low dollar cost of rearranging aquatory. Still, directionally, lower friction = higher volume, we're just debating the elasticity.