Finance is one of such use cases, but there's a lot more, and that's the use case for people not using GC, thus why I find this article (and the comment saying 500us is a solved problem) pedantic.

I wrote code profilers for instance, which also need perfectly predictable latency. I worked on L2 and L3 networking applications (bridging, routing, forwarding) that need line rate support. People working on audio sampling, or codecs have the same constraints, etc.

There's a whole world of applications where 500us is ridiculously slow. The article takes the OS as example, but if my OS has 500us random latency spikes, I would be horrified.