... Only the scale with the 4 silver dots measures your body. The connection is established spontaneously. The manual mentions several users (at least 8), which is not a problem, as the scale stores NOTHING. Either it is transmitted directly or it is gone... At least that's the case with my Mi.
No idea, but if you want to try it out for yourself, I'll sell you my scale for CHF 10 (including postage). I don't use it because I wanted a scale that gives body composition and this one doesn't. It's new (used 1x), but galaxus won't give it to me. It's brand new (used 1x), but galaxus won't take it back because it's been unwrapped.