Watching one of her videos, you can see that her theremin has a pitch display, showing pitch on a hex grid of LEDs. It must make accurate pitch a lot easier (although in no way "easy").
AFAIK Carolina only uses the D-Lev pitch circle for coming in on pitch, not for active playing. That's pretty typical for players who have learned on an analog Theremin, where they have necessarily been guided only by fingering techniques and their ears. Many Thereminists plug a guitar tuner or similar into their Theremin for this, but those sorts of tuners are rather sluggish. When you have a highly responsive tuner, then playing turns into an almost "paint by numbers" experience, and you are much more aware of the key and other song structure.