I vibe-coded a simple helper script. If I wrote it myself it would have been 1/3rd the lines, not covered most edge cases (some of which were completely irrelevant, some of which actually useful), and it would have taken me way longer than just checking if the vibe-coded code works (this was the "either it works or it doesn't" kind of task, not something where subtle errors could reasonably be introduced).
I skimmed the code and removed the line that deletes temp files to reduce the risk that it accidentally wipes my home dir and ran it. As I was trying to work with the data deeper, I noticed missing temp files, and realized that there were two other temp file deletion lines that I missed.
It's simply too much code for a human to reasonably read, but the speed benefits are real.
(My plan for the future is not reading the code more carefully, it's putting it in a sandbox and letting the AI play.)