I personally worked on digital marketing campaigns for years as a data scientist in a previous job, and have become entirely disillusioned with the entire notion (and I am not alone[0]). Its largely snake oil, and its effectiveness is incredibly overblown. But literally billions of dollars, large marketing teams embedded in every company, and some of the largest tech giants on the planet all have an incentive to drink the Kool-Aid.
[0] https://thecorrespondent.com/100/the-new-dot-com-bubble-is-h...