Glad you brought up porn because I believe that if you optimized any site's features just based on engagement analytics, you'd end up with a porn site with elements of gambling!
I'm kidding of course, but the idea is that analytics tell you a part off the user story, but doesn't answer the deeper "why" questions. It certainly has a place in tech, but it's less than what it's currently afforded.
Bender was on to something. "X but with blackjack and hookers" is the next untapped market for disruptive startups. We've worn out "X, but on the internet" and "X, but blockchain".