Thanks for the chime in. I don't work in fin or even adjacent to it, but in robotics we often have to correlate logs between multiple systems to fully understand a failure and in a lot of those situations milliseconds do matter— when did the sensor reading come in, how quickly did we understand it and alert the other unit, how does this line up with the timestamps on a security cam video we don't control, etc etc.
Quite common in real-time sports betting world.