When it comes to SEO, an important thing to keep in mind is your heading tags.
You know it actually does something other than give your heading a placeholder.
You could use anything to make a heading look different from anything else, which brings about the purpose of these useful tags.
In search engines, a robot is on the hunt for keywords and headings are a very good place to get them. But how does a search engine know what a heading is if one only uses or some other form of emphasis, using CSS styling to make it different? It doesn't!
Which is the reason why it's so important to use those heading tags instead of any other tag when you want to emphasize what a heading is. The search engine robots are looking for those tags in order to understand what your page is about and to gather important keywords for indexing. Headings are great places for keywords. Take advantage of them. For a useful resource as to how to organize your headings so that the more important things appear first, check out this link at CSS-Tricks.com.