Do you read the test suite of all the programs you run? I trust software because the authors have shown themselves to be competent and trustworthy. I expect authors to understand what they are doing, not just bashing into the guardrails until they get something that passes all the tests.
An LLM has reimplemented a 2 times faster version of a program developed by a team of dozens of brilliant engineers led by few of the biggest experts in compilers and programming languages in the world.
While maintaining 100% test coverage and so far compiling every single project that the original compiler did.
If your takeaway here is "yeah, but the other one has been checked by dozens of paid devs and an entire community", and still those dozens of devs with the backing of thousands of contributors could not make a compiler faster I can't buy say: "maybe we humans aren't as good as writing code as we thought and LLMs are exposing us".
In the same way you trust any build of the official compiler: it passes all of the existing tests.