Here's a simple idea that bitcoin accepting retailers could do to save costs. The basic idea is that consumers overpay by sending a UTXO for the product in its entirety, and the retailer returns the change in lightning/liquid OR creates a balance of credit in that retailers mint.

Here are some of the main advantages:

It makes good use of onchain UTXO's by not breaking them up and creating unwanted dust.

It looks like a "self spend" to any chain analytics.

It helps retailers balance their LN channel by creating more inbound liquidity.

It encourages more retail adoption of LN.

It saves block space.

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