Celery + RabbitMQ is hard to beat in the Python ecosystem for scaling. But the vast, vast majority of projects don't need anywhere that kind of scale and instead just want basic features out of the box - unique tasks, rate limiting, asyncio, future scheduling that doesn't cause massive problems (they're scheduled in-memory on workers), etc. These things are incredibly annoying to implement over top of Celery.

Yeah that list right there. That's exactly it.

We don't hate Celery at all. It's just a bit harder to get it to do certain things and requires a bit more coding and understanding of celery than what we want to invest time and effort in.

Again, no hate towards Celery. It's not bad. We just want to see if there are better options out there.