The whole benefit over zod seems to be perf, so could you do some benchmarking? I wonder if it’s worth it

Yes, the primary focus is memory efficiency; performance improvement is a side effect of that. From my own benchmarks, I have found that to be the case. If you're validating thousands of objects per second or working with memory constraints, the difference becomes quite significant. Happy to share the full benchmark code if you'd like to run them yourself!