QGC offline parameter editing concept

There is one thing in QQGroundControl I have not yet understood:
What is the off line editing parameter concept for?
There are files “APM\Plane3.9.OfflineEditing.params” same for Copter.

One can only edit parameters while connected to the vehicle.

The code first reads in the meta data from offline parameters and later updates them with the ones from the xml file: (e.g) APMParameterFactMetaData.Plane.4.0.xml and later updates the values received from the flighcontroller.
Why not just reading in the meta data from the xml file (e.g APMParameterFactMetaData.Plane.4.0.xml )
What benefit has the APM\Plane3.9.OfflineEditing.params ?


What I found out in the meantime:

ArduPilot parameter xml file does not contain info on the data type of each parameter.
The *OfflineEditing.params file enriches each parameter with its data type and component id.
For me remains open, what is the source of the data type of the OfflineEditing.params file?
Because the meta data as defined in ArduPiot src code, from which the APMParameterFactMetaData.Plane.4.0.xml is generated from, does not contain that data type info.

Is there any special meta data generator, or is the data type in off line parameters file, simply manually edited?