CUE(lang) and that we finally have a proper language for configuration and schemas. I think it will be significant in DevOps and anywhere we use Yaml or json for config.
I checked out Dhall back when I also found CUE. Definitely do not like it. The syntax is too different from existing configuration languages to see mass adoption. CUEs philosophy is much better outlined and reasoned, and comes from the same place as containers, kubernetes, and Go.
Another benefit of CUE over Dhall is that I can use CUE from Go. Very few people use Haskell, Go is an industry standard at this point