I've zero interest in counting absolute steps. Anything mounted to your wrists is going to have a margin of error. I use GPS apps for walking and cycling, so the Mi will provide an idea of activity outside of those, and as long as its error amount stays consistent I can compare the data across days fine.
Went for a walk today, Endomondo said 5 miles while Mi counted 4.5 miles of steps.
It's main use for me is to track sleep though.
It's £10, the FitBit and Garmin and others are 10x more expensive. If you want to spend that money on a more expensive way of guessing how far you have walked, be my guest