We’re taking about CVR voice only recordings aren’t we?
CVR in a single pilot aeroplane picks up a whole range of other useful pieces of information, Squawk7700.
The recording can be used to analyse the propeller RPM signatures which would indicate whether there were any variations to the engine power settings, for example.
Also, it can reveal the sounds of control and switch movements. In this accident, there is some uncertainty as to whether the flaps were extended for takeoff but retracted during the short flight. The CVR may have recorded the sound of the flap motor - or the possible absence of that sound.
Sometimes, discussions involving the passengers. For example:
Pax to pilot: "Hey, how do you steer this thing around on the ground? Is that little wheel there what you use?"
Pilot: "Nah, that is the rudder trim wheel. Only for use in flight. See, I will roll it all the way over but the plane keeps taxying straight ... see that?"