Hi Tobias, thanks for your interest.
Some answers..
1. I used the element because the documentation said i could.
2. Yes:
tiddlywiki.com, tiddler: HTML in WikiText.
3. I looked at the widget, but it came across a bit complicated for the functionality I wanted.
I work at a game developer, and wanted an easier, interactive way of describing every game entity (this especially helps programmers, which I am not).
I created png's of Flowchart state diagrams, after that I made html image maps of them. Programmers can now see a complete process in a Flowchart Diagram and get a detailed tiddler description of any entity when they click on them in the image map. So far tiddlyWiki satisfied my needs! :)