In the 8 years or so she's been working on it she's recorded about 100k thoughts. So, 1 million thoughts is probably enough to store everything you think in an entire lifetime. Thats a bit of a grim thought, but its probably about the right performance target for something like that. There's something very calming about knowing that if it performs well with 1M thoughts, its fit for purpose.
Its nice to have benchmarks like that.
For what its worth, I'd recommend explaining all of that with the benchmark explanation. "Measured on a 2017 macbook air with the text of War and Peace". Seeing Bear crash doesn't really tell me enough about whats going on.