Well, as long as you have an objective of WEBSITE_CLICKS then the primary purpose of what you are trying to achieve is clicks and hence that’s what the line item’s primary ‘concern’ will be, if that makes sense.
Beyond that, thinking about conversions, you’d want to use WEBSITE_CONVERSIONS rather than DEFAULT, irrespective of if you are using a primary_web_event_tag. Let’s just say using primary_web_event_tag and WEBSITE_CONVERSIONS together won’t harm you! 