For the microseconds-chasers, there's microwave relay links, say between Chicago and New York (ref e.g. https://bullseye.ac/blog/economics/inside-the-world-of-high-...). Sending a signal up a few hundred km and down again a few hundred km adds way too much latency, and signal-hopping between fast-moving satellites adds way too much jitter for "such applications".
For the microseconds-chasers, there's microwave relay links, say between Chicago and New York (ref e.g. https://bullseye.ac/blog/economics/inside-the-world-of-high-...). Sending a signal up a few hundred km and down again a few hundred km adds way too much latency, and signal-hopping between fast-moving satellites adds way too much jitter for "such applications".