According to linked in the author worked on Apache Arrow, so I suspect they knew about it. It feels like this is intended as a much more lightweight option, but would be interested to hear their take.
That's right, it's intended to be more lightweight since it's built with only Rust from the ground up. Apache Drill also only focuses on serving SQL as the user interface while ROAPI wants to provide a pluggable interface to support all use-cases. For example, we can plan graphql and rest api calls into query plan and efficiently execute them using Datafusion.