Usually the logarithmic display is more useful, because it presents a larger dynamic range with better detail at each value.
Frequency sweeps may be used by regulatory agencies to monitor the radio spectrum, to ensure that users only transmit according to their licenses.
For example, RF oscillators are measured for phase noise, harmonics and spurious signals; computers for consumer sale are tested to avoid radio frequency interference with radio systems.
Portable sweep equipment may be used to detect some types of covert listening device (bugs).
For instance, at American Super Bowl games, audio engineers monitor (sweep) the radio spectrum in real time to make certain that all local wireless microphones are operating at previously agreed-upon and coordinated frequencies.