Vojtech Ruzicka describes his decision to migrate his blog from WordPress to a static JAM Stack site using GatsbyJS, primarily due to issues with WordPress such as performance, security vulnerabilities, and costs associated with hosted solutions. He highlights that the JAM Stack approach, which stands for JavaScript, APIs, and Markup, offers a more efficient and secure architecture by serving static HTML, CSS, and JavaScript files through a Content Delivery Network (CDN), thereby improving site speed and scalability. Ruzicka emphasizes GatsbyJS's advantages, including its modern technologies like React and GraphQL, which allow flexible data handling and integration from various sources. He also notes the improved performance, ease of version control with GitHub, and the convenience of writing content in Markdown. Despite some initial challenges with maturity and features, Ruzicka finds Gatsby to be a robust solution that enhances the blogging experience by eliminating the concerns associated with WordPress, ultimately resulting in faster site performance and better SEO rankings.