I basically agree with that, though I'd say that lower voltage motors are sometimes useful in conversions, since they usually have a smaller battery pack than what would be in an OEM vehicle (due to weight, cost, and having limited space to put the battery). Lower voltage doesn't really stop you from salvaging all those other parts from an OEM vehicle. I think it's usually just the motor controller and DC-DC converter that run at the full pack voltage. DC fast charging is a problem if the charger doesn't support the lower voltage.
I have wondered whether the Hyper9 can actually run at a higher voltage without damage. I suppose the limiting factors are the insulation on the motor windings and the ability to dissipate heat. (The motor demagnetizes if it gets too hot, which is why the motor has a temperature sensor so the controller can back off before that happens.) The Hyper9 comes with a motor controller that's limited to 180 volts (that's for the 144v nominal version). I don't know if anyone's tried to run a Hyper9 with a different controller that can handle much higher voltage, like 300 or 400v.
I have wondered whether the Hyper9 can actually run at a higher voltage without damage. I suppose the limiting factors are the insulation on the motor windings and the ability to dissipate heat. (The motor demagnetizes if it gets too hot, which is why the motor has a temperature sensor so the controller can back off before that happens.) The Hyper9 comes with a motor controller that's limited to 180 volts (that's for the 144v nominal version). I don't know if anyone's tried to run a Hyper9 with a different controller that can handle much higher voltage, like 300 or 400v.