As a marketer, it would be useful to be able to do more with the open or non open data. For example, if I wanted to be able to identify the customers who never leave a review after being sent an email. The ability to be able to filter based on volume of reviews sent by never opened on a grouped individual level. I may want to extract a list of those contacts and target them via alternative channels. Knowledge of that behaviour could infer other marketing activities or interactions with the brand that a particular group of customers are displaying.