Building landing pages in HubSpot should not negatively impact your SEO efforts. In fact, HubSpot's landing page builder is designed to be SEO-friendly and includes features like custom meta descriptions, canonical URLs, and responsive design that can help improve your rankings. However, if you already have an established SEO strategy and infrastructure in WordPress, it may be beneficial to continue building landing pages there to maintain consistency and avoid any potential disruptions to your SEO efforts. Ultimately, the decision should depend on your specific needs and resources.