Interesting that the Digital Wellbeing features that were teased at IO aren't being launched today, but part of _another_ beta that you have to opt in to. (And Pixel series only?)
It's almost like they're there to satisfy some strategist in Google so they can say to governments that they're trying, while not actually believing there's any issue and with zero chance of any user take-up.
It seems like tracking began with the last beta update which I installed on July 30th if I remember correctly.
By the time Android P actually makes it to non-Pixel devices, the beta will have long since ended, so this doesn't really matter.
Android P is available for the Essential phone[0] the same day as the Pixel. Technically, every device in that was enrolled in the Android P beta could have also had it day one.