Propellent is finite, so you want to use it as rarely as possible.
A reaction wheel is by itself infinite (assuming it doesn't break), but eventually it saturates and you need to desaturate it, which basically means spinning the wheel the other way while spending propellent to maintain position.
All of this is to say, reorientation is an expensive process especially if refueling isn't an option.
You can reorient as much as you want with a reaction wheel, and the only cost is electricity.
That’s true, but a failsafe automatic reorientation mode after two weeks with no communication from Earth might be a useful feature
I agree. It probably doesn’t make much difference now. There are very unlikely to be any important data that will be lost. The mitigation process they already implemented seems prudent and sufficient
During earlier parts of the mission, like planetary encounters, it would make a difference. Even a two week wait could be much too long in those circumstances.