I tried it once and it instantly showed no results, but then I tried it again and it returned results in <1s. Just try it with a bunch of queries, I think there's caching too so it's hard to gauge performance properly.

The blog post about the demo is from 2021 and they haven't promoted it much since. I'm surprised that they even kept it online, according to the sidebar it was ~$810/month in AWS at the time.