The Theremin is an amazing instrument indeed, especially when someone has exceptional control over it.
I saw a prominent Theremin player (can't recall the name) play an entire evening with our local symphony orchestra and was completely entranced, both visually and aurally, by his performance and control. He made that thing sing and and the sounds produced were truly ethereal...I was pretty amazed by it all and he blended/augmented the symphony instruments in a most interesting way.
It was Moog Theremin (with some custom mods IIRC) with MIDI control which he used to trigger sounds and audio events as well.
At the end of the evening he let people come up to see and try it and to ask questions. I got some time on it and
tried to play the vocal melody from "Theme From Star Trek" (the original series) and instantly gained a whole new appreciation of his talents and how cool the instrument is. I sounded like a warped record/dirty capstan tape recording of a wailing cat lol.
There is something entrancing about watching someone play an instrument in 'thin air' without touching it.
I think you might be even more impressed with Carolina Eyck then!
Interesting, never heard of her and will have to check that out...!