From reading "Quantum-Limited Atomic Receiver in the Electrically Small Regime" (PDF) [1], it seems there are 3 main advantages to Rydberg sensors, wide frequency rage (DC to Ghz), very small sampling volume, and non-interaction with the RF fields.
The wide frequency range means that you can use the same sensor for a wide variety of measurements, calibrating it down near (or at) DC, and later using it to make accurate measurements of RF or Microwave signals.
The small sampling volume means that you can probe at resolutions far smaller that the wavelength of the frequencies being measured, so you can measure the field strength in 3d (with appropriate mechanical scanning hardware) of antennas and other gear, something you can't do normally, because normal antennas are much larger than a wavelength.
The isolation means you can effectively probe almost any system and without disruption. Unlike measuring voltages with a voltmeter, there are literally no conductive elements that would reflect or refract RF signals, short out dc signals, or induce currents from present magnetic fields.
The wide frequency range means that you can use the same sensor for a wide variety of measurements, calibrating it down near (or at) DC, and later using it to make accurate measurements of RF or Microwave signals.
The small sampling volume means that you can probe at resolutions far smaller that the wavelength of the frequencies being measured, so you can measure the field strength in 3d (with appropriate mechanical scanning hardware) of antennas and other gear, something you can't do normally, because normal antennas are much larger than a wavelength.
The isolation means you can effectively probe almost any system and without disruption. Unlike measuring voltages with a voltmeter, there are literally no conductive elements that would reflect or refract RF signals, short out dc signals, or induce currents from present magnetic fields.
[1] https://arxiv.org/pdf/1805.09808.pdf