OK, is it as simple as changing the most basic unit of account from sats to millisats? How does that "transformation" happen in Lightning. Or is it simply because any rule can be made up in L2 networks?
Yes, and making it unenforceable onchain (as dust outputs once again!). Some are critic regarding that choice.However, accounting for such small amounts are really handy : for example for the fees. Fees are denominated in msat and most are below the thousand msat, without such an accounting system how could fees that low (or that precise !) be enforced ? Paying one whole sat but once each X forwarded payments ? That's not viable.
OR for example, the possbility of a more than 6 digit per Bitcoin world. Instead of breaking Bitcoin's social contract by adding more decimal places onchain, do it in L2.
