It's part of the onboarding of any Facebook Ads user (i.e., advertiser) to implement the Facebook Pixel on their site.
Without it you're not going to achieve much on Facebook as you need to feedback their system when a particular ad had an impact so that they can model the ad delivery accordingly and get you more converting users. Whatever your conversion is (viewing a page, registering, purchasing).
Without it you're not going to achieve much on Facebook as you need to feedback their system when a particular ad had an impact so that they can model the ad delivery accordingly and get you more converting users. Whatever your conversion is (viewing a page, registering, purchasing).