Unlike the other UTM parameters, UTM content parameter is optional – you might want to set it or skip it, depending on the need of the hour.
UTM content parameter is widely used during A/B testing, and helps in determining which content is performing better than the other. You might have two blog posts talking about your same product, yet one would drive more traffic than the other. How would you determine that which blog is most engaging? This is what content parameter does. It helps you in tracking the success of your content.
However, it is highly recommended to adopt the best practices while setting the UTM parameters and follow the same convention throughout if you want to keep things simpler for you, or else, you’ll end up with major confusion with no clear data.