I love the idea of the auditory Seviroscope, because anything that can be translated into sound can become a mechanical movement. The simplest example of this is a seismograph-type rollout with the bouncing needles that can record ambient wind measurements over time.
Instead of having to rely on eyeballing locations and trying to keep written records, the Colleges and the Elector Counts can send out surveyors to any location they please and have a relatively accurate understanding of what the mystical environment tends to look like in an area over the course of a week or month.
The main use for that is noticing sudden spikes in uncommon winds that can point towards important environmental changes.
Build-ups of Dhar or the other Malefic Magics seem like the first use case, but you could maybe also use it to see if the Ghyran in a field is going up or down over the course of a week, which might be able to indicate if a set of crops might be going bad -- a sudden bout of Ghur might let you tell the difference between an incursion of hiding Beastmen or a pack of hungry animals.
You can also use the devices as a defensive type of vetting. If a person pings Dhar that's definitely a Hint, and hiding that sort of thing is not easy or quick.
Vetting-scopes along the halls can also detect large quantities of Ulgu; it's a bit of a self-own, but if I recall correctly Invisibility is mystically visible, and the Scope telling guards that Ulgu is in an empty hallway of, say, the Imperial Palace is a pretty good use-case.
It would be very expensive, but you could also employ an auditory Seviroscope as the mechanism for a straightforward trap; Dhar cutting a tripwire as surely as a misplaced foot.
