Sure, but it's not a competition. In the broader fedi there are instances using all sorts of stacks, including PHP-based ones (like Pixelfed), and these have instances that are huge and performant.
I do prefer the Rust stack to handle my data, but it's in no way a cut and dry case. And looking at https://kbin.social/stats, I don't know if any Lemmy instance would have handled that ind of traffic much better.
Huh. That's surprising. I just joined https://fedia.io/m/cybersecurity from my Lemmy account on szmer.info.