I enjoy the comparison between ecash and Ethereum as I think you’re mostly pointing to the ability of the Ethereum foundation to reverse transactions. I don’t think Ethereum folks would prefer the comparison tho. The difference is ecash is very purposefully built to give the creators total control of what backs it.

If you wanted to make this argument, you would want to make it clear that ecash is not Bitcoin, and any ability to convert to Bitcoin is based on the goodwill of the ecash creators.

Said differently, ecash tokens represent a deposit backed by the full faith and credit of… someone.