At work they run regular health challenges where each team submits their daily steps. These are then averaged on a weekly basis and compared to the other teams. I assume there is a prize.
Since when did the idea of your employer intruding to such a degree become normalised? Not only is there the use of such ‘nudges’ to encourage behaviour but also the voluntary surrender of such personal data. In this case, of course, it is entirely innocuous - most people could walk more, the data sits in a spreadsheet for a few months before getting deleted.
But you are being trained. The employer, the Boss, has determined this is the Thing You Should Do. Now perform surveillance upon yourself and report the data. Use the bug in your pocket to feed the machine. Slippery slope arguments are often bullshit, but the idea of this self-monitoring to align to employer-mandated health goals feels like a precursor to what may come later.