I read about these now and then. For people with anxiety when they step on the scale, there is no display. They connect with your phone using WiFi or Bluetooth. You can find out your weight or just a general "your weight is stable", "you're slowly gaining" etc. Or you can ignore it and it won't tell you anything.
Cost would be $10-20 more than an equivalent scale without that ability. There would be no monthly/yearly fee.
The reason why I am asking is because I'd love to work on an electronics project like this. It would be for sale on a website like Amazon, and have a typical one year warranty.