Use blockquotes for blockquotes. Use headers for headers. There is no guarantee that blockquotes will look like nice headers on all Stack Exchange interfaces, including the desktop, mobile, and Android/iOS apps. Furthermore, we expect the site to be redesigned soon for graduation, and blockquote rendering may change.
In fact, now might be a good time to make a suggestionmake a suggestion for how headers should be rendered in the new site design.
