geo-ip has never returned the correct state for me (across 3 different ISPs). The automatic Timezone detection on phones also rarely works correctly here.
So I can easily believe that it’s wildly inaccurate for a significant amount of the world.
Our goal was not to use this to orchestrate a global CDN, it's just one of the many use-cases and can be combined with anycast easily. This is just one example and we're not really trying to push GeoDNS specifically. What we envision is smart load balancing, backups, dynamic routing for validation or service discovery and a bunch of other things that are currently very painful to do. GeoDNS is an old concept and can be solved much better without scripting anyway.
In terms of accuracy, it is generally very accurate on a country level. Anything else is pretty useless.
So I can easily believe that it’s wildly inaccurate for a significant amount of the world.