Only reaching out to extremely high/low scores is just one example of the kind of trigger conditions you can set in an automated workflow. In the example in this article, we only want to talk to people who are “enthusiastic promoters” (≥9) or “unhappy detractors” (≤1).
One reason to try this approach is that these folks are the most likely to be emotionally invested in the product (whether in a positive or negative way) and will likely be more willing to take time out of their day to speak with you.
Of course, there’s nothing stopping you from reaching out to everyone, if you’d like! All you have to do is customize the trigger conditions to your needs.