Why HTML 5 still have support for Presentational elements?
Two reasons come to mind:
Because some people (not me, here is a primer about this opinion and here are the WHATWG FAQ about this) don't think of them as presentational. They argue, that
<b>has semantics of its own, for example, where<strong>is not right and the text should be bold anyways (IMHO therefore we have<span>)Because HTML5 has a pragmatic and backwards compatible approach: What worked in HTML4 should work too in HTML5. They argue, that this is why XHTML2 died.