So that the display can begin
An ad is an element (e.g. a piece of HTML code, a URL, etc.) that publishers will install on their website so that their visitors can see your campaign.
A campaign cannot start until you add media.
To animate my campaign
By regularly adding new ads, your advertising campaign is more visible and more animated.
Indeed, by proposing new advantageous promo codes, visuals that adapt to the seasons (summer, back-to-school, etc.), your publishers will put you in the spotlight better and Internet users will convert better.