I hate this scale, it says low battery and shuts off after just 3 months of sitting in the drawer. It infuriates me that there’s still a lot of energy in the battery, I can use that in remote controls with no issues
If there’s enough battery to say “low battery”, then there’s enough battery to show the measurements!
Batteries have one advantage over over supplies: extremely low noise. Even an good LDO will bump up the noise floor, and a cheap lcsc part will do so too. Plus you’s want a reasonably low dropout and quiescent current, which also increases price. Maybe 10ct in volume is reasonable for such a part - and yes, that will absolutely eat the margin