I’d argue the value is portability over custody. Custody is the liability you must accept to ensure portability. If someone chooses to trust a system like DNS to help them mitigate that risk, so be it. What is more likely… someone loses their key or a total takeover of DNS? Either way, using DNS + a .json file stored on a fileserver to map your keys to a username does not mean you have relinquished control of the keys. I could argue you have added resiliency and redundancy to the underlying keys without compromising their utility. If nostr can’t rely on the most basic aspects of the internet to function then it will remain a curiosity.