I am a fitness professional for the past 10 years and I’ve used it. Personally, I didn’t find it super useful and ultimately not worth the cost.
I am pretty in tune with my health so I try and do the basic things right (sleep enough, eat relatively clean, de stress, recover from whatever) and when I don’t I can feel it.
For people who have never really paid attention to that or people who just love data, I can see some benefit.