It's fine to have LLM skepticism as a default, but here it's not justified. Google is showing here that the LLM-written harnesses improve massively on the harnesses in oss-fuzz that were written over many years by the combined sum of open source security researchers. Most dramatically, they improved tinyxml2 fuzzing coverage by 31% compared to the existing oss-fuzz harnesses, through an entirely automated flow for harness generation by LLMs.
Whatever engineering technique you are imagining would be better is not one that humanity actually applied to the problem before the automated LLM harnesses were written. In general, writing and improving fuzzing harnesses is extremely tedious work that is not being done (or paid for) by nearly enough people to adequately protect critical open source software. The LLM approach is a legitimate breakthrough in the field of open source fuzzing.
Fair enough, interesting, and plausible! I looked at the first link and saw it as more of a capabilities demo, but didn't dig into the Google one. I'm mostly just encouraging thoughtful reflection on tool choice by raising questions, not making a case against. Very cool.
What matters for engineering is how that technique compares to others in the context of specific requirements.
A big part of "falling for hype" is in mistaking a new and capable tool for the being the right or oprimal tool.