Is it possible for a sleep tracking app to work in a useful way? It could tell you that your sleep is interrupted a lot, restless, rarely goes in to deep sleep - but is that actually useful information? How could you use what it's telling you? It's not enough to only know what's happening. You need to know why it's happening in order to affect changes that might improve things, else you could make things worse, or just waste any time/money you're spending trying to improve, or miss an underlying cause that indicates something is seriously wrong..
When I reviewed it, my take was that it might be a low cost way for someone who felt tired a lot to collect some basic data before deciding to go in for a sleep study or other medical tests.
