I think ecash and/or fedimint solutions is the best way a bitcoin standard is implemented.

In the future:

L1 - Settlement layer and place where major funds are moved. Equivalent to wiring funds today. Basically too impractical for your everyday needs but critically important as this runs the whole thing.

L2 - This is the credit card layer. This is the rails that the regular economy is built on.

L3 - Ecash/Fedimint - This becomes the operability layer which is the UI for the Bitcoin standard.

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