When the sakai.iframe.myworkspace (web tool) saves the description it processes it when it saves and escapes all html. The site info tool only (when viewing the site) only does it on the display. So you can save content in site info that you can't on the my workspace, and display content on my workspace that it assumes was already escaped.
There's no security issue, but it does things like prevents you from embedding youtube videos on the my workspace directly (instead you have to do it roundabout by editing the description in site info)
I'm going to change this so the myworkspace tool does a process formatted text on output only, then it looks good in both areas. I texted that script tags were blocked and iframes were working.