Indeed, I design similar equipment for industrial use. Non invasive blood glucose has been a holy grail of analytical technology for decades. Lots of smart people have gone bankrupt trying to solve this problem. The sensors are probably good enough already. Algorithms for sorting out massive libraries of spectral data exist. It's a hard problem. That's not saying Apple doesn't stand a chance, but that they're entering a very mature space.
Indeed, but those successes have tended to be in design and marketing -- not to denigrate those fields, but this is basic science, and hasn't even been done first yet.
