Really interesting indeed, the carbon paper / enveloppe analogy is great to grasp a how it is done, and the privacy improvement including what ecash allows in term of atomic multipath payment from multiple mints is quite interesting.

How I see it for Bitcoiners in the future:

-savings+ big tx (real estate, big purchases in general)--> Bitcoin

- day to day payments --> hybrid wallets :

self custodial LN (with LSP or not) coupled with an ecash wallet. The self custodial Wallet could top up the ecash wallet at will, allowing better privacy to send from many mints and asynchronous payment if no satisfying solution is found by then.