Fc/Fc+ is a very handy redox couple that is stable to store and easy to use. You can easily add a bit to your solution at the end of your CV experiment and use it as an internal standard. This makes the use of Fc/Fc+ very straight forward and is therefore a common reference system.
Fc/Fc+ is commonly used to calibrate a reference electrode in organic solvents.Then, the measured potentials are converted to NHE or SHE, which are used for calculations