BPMN 2.0 is the open standard for process models (ISO/IEC 19510). A BPMN model says who does what in which role, where decisions branch, what runs in parallel, what starts a process, how it ends and where it hands over to the next one.
Process mining usually generates directly-follows graphs from event logs: which activity followed which, and how often. They are good at frequencies and throughput times, but they show no roles, no decision logic and no parallel work, only the steps a system logged, and on real data they quickly turn into spaghetti.
Because BPMN is explicit, Rameo can check every model and diff AS-IS against TO-BE, documentation and automation can build on it, and other BPMN tools open the same file. Your processes never get locked into a proprietary graph.