I am not even challenging the need for KYC, but I would challenge the expectation that USD will remain king for the foreseeable future.
If the idea is, like you said, just about being able to convert between different asset classes, we could have OTC desks that would be taking crypto and (after following proper KYC/AML regulations) giving you any of stock/bonds/real estate titles/commodities/etc, and vice-versa, without any need of USD as intermediary.