We currently always include two versions of various buttons in the page HTML: one for visual enhancements enabled, and one for visual enhancements disabled. This is wasteful and probably affects page load speed negatively.
However, we need it to support the "Read as wiki page" button that can toggle visual enhancements off without reloading the page.
Once we remove that feature (T280417), we can change this, and only include one version, depending on user preferences.