Oh sorry to clarify. The smartphone is not necessary to pay with this. In the field it is used just like cash (older concept used at ethDenver before covid: htt

Oh sorry to clarify. The smartphone is not necessary to pay with this. In the field it is used just like cash (older concept used at ethDenver before covid: https://twitter.com/alexmasmej/status/1228771055524704256?s=21&t=y8i_Sr2wsfReiuegiYzMlA https://twitter.com/alexmasmej/status/1228771055524704256?s=...) The smartphone lets one validate the funds are stored on the note. This dynamic exists with cash too. In high trust/low value transactions we skip validation. In low trust/high value scenarios we don’t. Technically I can make the case one needs a highlighter to spend or receive American dollars to validate the note is authentic by checking the acid content of the linen substrate. In practice I don’t when conducting peer to peer payments but would when conducting C2B payments of a certain nature. Validation is an optional step which correlates with the trust environment and varies greatly by market. Given the nature of cryptocurrencies it’s imagined there would be stronger correlation with validation initially; then become lax as notes were commonly circulated or going through certain chokepoints like ATMs; tighten in regions were counterfeit notes were introduced. But strictly speaking? These style of notes have been deployed in marketplaces where a smartphone check wasn’t necessary or appropriate.