The elevated status this instrument once held can be inferred from the medieval images at the Bayeux cathedral of angels playing the jews harp. While to a modern ear its springy, high pitched rattle sounds odd, perhaps even comical (probably no thanks to its use in providing modern cartoon sound effects) it is nevertheless used in some shamanic traditions as a trance inducing instrument. The sound can be very like modern synthesizer tones, the main difference being that a jews harp is primarily a percussion instrument with a very limited musical range.
It would, sensibly, operate much like drums in other magical traditions -- the use, obvious, for stirring up spirits, clearing the air of negative forces, and for its playing being the kind of dull, repetitive task that often induces trances and spiritual sensations. The curious sound, which to the ears of the ancients sounded supernatural and otherworldly, would also carry a special power all of its own, filling the atmosphere with mystic forces.
It is not as easy to play a European style jews harp as it initially would appear, and the little metal pluckers are infamous for damaging the player's teeth if used incorrectly. Some of the Asian styles, like the Vietnamese dan moi, are a bit easier to use since they don't require being pressed against the teeth to resonate.
Whether used for trance or for musical enjoyment, a jaws harp can be employed for very interesting sounds. I personally love listening to the Indian arrangements, usually accompanied by a drummer: