No problem - battery voltage in each cell, obviously, in real time. Variations (in real time) between individual cells. Total current draw. The relationship between stick inputs and actions. Motor RPM and load for all four motors. Mod values, ascent and descent rates, horizontal speed. Which mode the craft was in at the time. Satellite count. Battery temperature. IMU temperature. Altitude, both in relation to sea level and take off point.
The things that make assessing what went wrong in the event of a crash useful. IMHO, healthydrones doesn't address these. That said, it's working on the information that is stored in Flight logs in the app - whereas for the 'useful stuff' the .DAT file has to be retrieved. But that's where the real information is. And using budwalker's data converter and dumping the file into luap's dashware is very easy once you have retrieved the .DAT file.