Using pop-ups on landing pages in campaigns has several drawbacks. First, pop-ups can disrupt the user experience, frustrating visitors and increasing bounce rates, especially on mobile devices where they can be hard to close or navigate. This often leads to lost potential conversions. Second, pop-ups may slow down page loading times due to additional scripts, negatively impacting overall website performance and search engine rankings. Third, many users use ad blockers or browser settings that block pop-ups, meaning your message might never be seen. Finally, pop-ups can complicate conversion tracking and analytics, as some tracking tools struggle to capture interactions within pop-ups accurately. Overall, pop-ups risk annoying users and reducing campaign effectiveness if not carefully implemented.