Not sure if it makes sense or Google has found way to remarket their ads.
https://www.statista.com/statistics/...rce-usage-usa/
Note: ^^ the USA -- not global
Share of digital device users in the United States who used multiple devices in path to purchase as of 4th quarter 2016
" About This Statistic
This statistic shows the share of digital device users in the United States who used multiple devices in path to purchase as of the fourth quarter 2016. During the survey period, it was found that tablet users were most likely to have used multiple devices in the path to purchase, as 36 percent of tablet buyers had done so."
Google has probably lost a lot of volume with their AdWords changes -- volume and not revenue.