If you knew what you were talking about then I could probably answer better. Who is herf?
Short answer is:
There is no reason for html to be enabled. BBcode is enabled. BBcode is just *safe* code that is translated to html when the post is rendered. This is so rude people cannot break the pages with nonstandard html or add things that shouldn't be there.
The html you would probably use: text color, size, bold etc, linking, pictures....it is all available with BBcode so there is no reason to actually enable html.