Which is exaxtly what I said, that it’s fast enough for most use cases.

In theory though, you will “gain performance” by rewriting it (well) in C for literally anything. Even if it’s disk/io, the actual time spent in your code will be lower, while the time spent in kernel mode will be just as long.

For example, you are running a server which reads files and returns data based on said files. The act of reading the file won’t be much faster, but if written in C, your parsers and actual logic behind what to do with the file will be.

But it’s as you said, this actual tiny performance gain isn’t worth it over development/resource cost most of the time.