Once I asked myself a question: how google fit, a fitness information hub, synchronizes all the information coming from different sources.
To be sure I did an experiment. I turned google fir synchronization off in mi fit (official application for mi band), said Endomondo that I started walking and wend to the office.
My Endomondo data was stored in google fit - fine.
Then I turned syncronisation on back in mi band, and saw that now google fit contains information from mi band only. Information came from Endomondo is removed.
Ok, probably, this worked this way because it was similar activities. Therefore I said Endomondo that I was riding a bicycle. Same result. Only mi band data in google fit.
google fit cannot be used as fitness data hub, it cannot aggregate data from different sources. This is rather strange since we all waiting for internet of things, when you could have much mode fitness devices in use.