All cool stuff for developers, I am sure.

This economist's perspective is different, especially as OP relates to merchants and shops. It is becoming quite clear that Bitcoin is stuck on (minimal) first order merchant level adoption and it is reported to be regressing in El Salvador. The reason for this reality is rooted in economic laws.

For me, Lightning Network is a key part of what should become the abstract wholesale money layer of Bitcoin. Its key function will be to ensure verifiable honesty of the retail money layer nodes which are much better placed to handle privacy for monetary fungibility and political censorship resistance.

These are very different requirements to the ones assumed in this piece.

Chaumian e-cash is a far simpler tech base to build this, the key complexity being assured base money redeemability. Doable though. And LN can stay simpler, too.