While the destination (KPIs) is important, the journey isn’t any less important. User flows paint a visual route of your users’ intent throughout the app. It also yields a lot of insight on your app’s usability and how well it’s functioning -- for example, are paths logical or maybe entirely illogical? If the latter, this is a cause for concern and a departure point to begin taking action on improving your app.
Not only does this piece have great information, there are also great images on how to start implementing user flows in your analytics.