Quite interesting review to read as we will be seeing more health functionality coming in earbuds, but the big question remains that no-one has earbuds in their ears 24/7 (that's probably not healthy), and yes pace and stride measurements are not really going to be good.
I'd expect to see more happening with temperature, heart rate, etc and could be very relevant for those who do not wear smartwatches. Right now, the big focus on health seems to be evolving in the smartwatch category, and is actually driving the sales f those devices. Maybe ear buds though will still carve their own niche in the near future.
See The World Isn't Ready for Health-Tracking Earbuds
The Amazfit Powerbuds Pro delivers great ANC on a budget, but the health features leave a lot to be desired.