Root vs Fruit
Knowing what is right causes our minds to be full of doctrinal head knowledge.
Doctrine absolutely matters, and is of utmost importance.
However, doctrinal head knowledge can be dangerous, because the Bible warns that: "knowledge puffeth up."
Doing what is right, living right, and loving people is how we put our doctrinal head knowledge into practice.
If the motive of someone's "systematic theology" is designed to win arguments and doctrinal debates against other Christians, they've missed one of the most important doctrines found in the Bible: "charity edifieth."
Charity is a Bible doctrine. And although right doctrine is the root. Right living is the fruit.