All I know is this reminds me a lot of high school where we had to always compute std dev in problems, homework, and sometimes labs, but nobody really ever explained how to interpret it. It was always like "This is std dev. This is how you compute it. Make sure you put it your tables and report."

Eventually someone (or something) did explain it, but once I understood it, it became clear that it wasn't always a sensible thing to be asked to calculate but was instead just an instinctive requirement.