you want this to be applicable to UTXOs but you completely fail to show how UTXOs function like cash bills. a 100k sat utxo with coinjoin history is NOT "considered entirely equivalent" to a 100k sat straight from a miner. your peer might not care, but he CAN *distinguish* between them. unlike cash bills. for a value transfer system to be fungible, units must be BOTH 1. equal and 2. indistinguishable. therefore UTXOs are not fungible like cash bills.