That's a bit unfair given that the project didn't mention Kafka in it's README and different products have different suitability at different scale and this could simply be a "if your traffic is low and you need this functionality, this will suffice" thing or just an academic interest in producing an ordered distributed message queue.
But as you're asking: Proven ability to consume ~5+ million messages per second with a similar or less hardware requirement than Kafka and high reliability. Well document set of edge cases / compromises where applicable and a high degree of observability. Well understood operational requirements, and SRE runbooks (or just a lot of Github issues that go into how to handle various scenario). An active community of people to assist, and more than 1 committer.
That's the "off the top of my head" thing. YMMV.