To me the most useful feature was actually just the timeline view. Being able to see all of the events and telemetry updates from all agents and correlate them to some line plots was already a huge help. I think Rerun should actually make the timeline view just another "view" [0] so that I can have additional timeline views with specific filters. Seeing the discrete pips in the timeline for different events and channel updates is really helpful.
Also we already have infrastructure to log and for live telemetry streaming so we don't integrate with the SDK directly in the deployed software and instead just have an adaptation layer to take logs or live data and push it through the Rerun SDK. I generally feel it's better to separate the data generation and logging from the data visualization, though I could understand directly integrating the SDK as a fast solution if the infrastructure is not already there. I hope the use case as the data offload/logging for a system doesn't become a focus sink for the Rerun team.
That said, I do appreciate the simplicity of the Rerun SDK API design. At first I wanted to try Foxglove but it seems pretty tied to the supported formats (which we weren't outputting for heritage reasons) and my eyes glazed over when I saw how much work (I perceived) it would take to integrate with their custom websocket interface. This was all spare time exploration so I basically dropped it once I saw how much code there was in the example [1].
[0]: https://rerun.io/docs/reference/types/views
[1]: https://github.com/foxglove/ws-protocol/tree/main/python/src...