I have used for more than one year a conventional test bench with a vertical propeller.
Advantage: absence of ground effect.
Drawback: volume of the device and horizontal air flow, everything is blown away on a two meters distance.
Super Simple Test Bench has none of these disadvantages.
It's small, air flow is vertical and air speed below the prop is insignificant.
That means it can be used instantly on your desk surrounded by sheets of paper, nothing fly around it.
There is also no ground effect, ceiling being 2 meters above the prop, and no drag due to arm supporting the motor.
Values recorded with the two devices are practically the same.
Build one, it's easy, you will compare with what you have got before.