It simply did not work. And the reviews on Google Play were 1 star reviews, because the app simply stopped working.
I wasn't using this app for years, since I've written a Python script to read out the scale via a Raspberry Pi, but I wanted to change some weight thresholds in the scale, which my script didn't support, so I installed the app, after two years of not using it.
I think this app messed up the scale. It connected once, then never again. I even installed versions from 2 years ago, assuming that at least that would work. It didn't. I've tried this with 3 different phones. Pixel, Motorola, Xiaomi. No success. I've rebooted the phones several times.
So I searched for the Bluetooth codes which were responsible for setting these thresholds in the scale, and added them to the script. The script worked fine and did set the new values.
But now I have the issue that the Raspberry Pi often fails at connecting to the scale. It's annoying, but at least the scale has a buffer for several measurements, and once it can connect, it downloads all the measurements.
For others this simply means to throw away the scale or use it offline. Granted, it was a cheap one at around 15 €, but that's no reason to break things.
I'm currently so angry at this.