In general, cash is fungible. You gave an example of a "shade of fungibility" with marked cash used in crimes. Unfortunately, reality is not binary. Ethereum is

In general, cash is fungible. You gave an example of a "shade of fungibility" with marked cash used in crimes. Unfortunately, reality is not binary. Ethereum is fungible to the (increasingly small) non-OFAC compliant nodes, but non-fungible to the OFAC compliant nodes.