Didn't they say they were going to open-source some model? "Fast and good but not too cutting-edge" would be a good candidate for a "token model" to open-source without meaningfully hurting your own bottom line.
I'd be pleasantly surprised - GPT-4o is their bread and butter (it powers paid ChatGPT) and QA seems to be slightly ahead on benchmarks at similar or lower latency (so very roughly, it might be cheaper to run).