Seems like we can just build light weight APIs on top of this. And port 53 is always open too just 80 and 443.
DNS is designed for caching. You can use DNS for anything that is public, idempotent, and immutable (or at least, slow-changing).
Some DNS server allowes very lowe TTL, so maybe not so slow changing. Can we set it below 1 min? Or does that depends on some standards?