Simple analytics work fast, but cannot avoid third-party effects: why don't you try multivariate statistics?

I've seen a dichotomy between "analytics" vs. "data science" (or "statistics) in several teams of web marketing, because people may feel analytics is simple, fast and work well while statistics is hard to learn, complicated and time-consuming. In the latest post, I argued about the dichotomy from a viewpoint of analytic accuracy and pointed out a pitfall of simple and fast analytics. Essentially, any kind of multivariate data may contain third-party effect: but I feel not a few people neglect it. To avoid such a pitfall, multivariate statistics is important.