The claim is that this removes the human bottleneck (aka SFT or supervised fine tuning) on domains with a verifiable reward. Critically, this verifiable reward is extremely hard to pin down in nearly all domains besides mathematics and computer science.
By verifiable do they mean it in the complexity theory P/NP sense of the word?
For this problem we don't care if it's possible that sometimes there are things that aren't verifiable, or the answers aren't exact, we just need training signal.