I always wonder who the audience is for these things, as I assume that most people in some kind of software engineering principle will have gone to university, but I suppose this is a good read for anyone who went the bootcamp route. Use cases are very important and it oftens stumps product owners when I ask them about use cases because they haven't really thought out what clients are asking for and how it relates to users. Many "super urgent" feature requests can be reprioritised when the product owner understands how it actually relates to the system.