I'm quite curious. Friends I've talked to have been very pessimistic about accurately measuring blood sugar via a watch.

If they are actually able to get an optical measurement which is good enough for MoM or WoW trends, I'd agree it's pretty big even if they can't provide anything precise enough for real time / daily use. Just being able to roughly validate diet changes for women with PCOS could be very impactful and that's the smallest of the 3 populations you called out.