And, as mentioned, you don't want the helicopter flying anywhere near the rover for fear it would collide and damage the rover.

Also, not really ironically, the helicopter's own solar panels (which sit above the rotor blades) are collecting dust, and that plus the lower sunlight during this part of the Martian year have significantly reduced power levels. They have had to implement measures to reduce power consumption, which will reduce the operating life of the internal batteries. It is possible we won't see any more flights, not sure yet.

I assume there are also worries about letting the helicopter fly near it, in case of damage