* how does this compare to a reading from a finger poke,
* and the subcutaneous reading that you get from a CGM?
Finger prick measurements are still the gold standard in terms of accuracy. The method in this paper is still in its early stages, but it's already showing promising results. Compared to CGM, it's significantly cheaper and more accessible.
Maybe one day it will be integrated in commercial ear buds.
I imagine the ideal market for this product is diabetic children; both the finger pricks and CGM need to break the skin, while this is the equivalent of picking your nose kinds of easy. Even assuming it's only 50% as accurate as other methods, the ease of use in an otherwise difficult situation is valuable.