When Google Declared FitBit Last Month, they clearly mentioned in the blog post that”Fitbit health and wellness data will not be used for Google Ads.”
A thing to note that: Google particularly said that they would not use the data for google ads.
John Mueller Tweeted on it:
On the one hand, I'd love to encourage more people to be active, when it's just a matter of getting up & doing something. On the other hand, there are many who legitimately can't, for many reasons, and we should take care to be as inclusive as possible.
— 🧀 John 🧀 (@JohnMu) November 2, 2019