I can understand why Apple - or Cingular - doesn't want to have 3rd party software on the iPhone: You could install some Skype or other client and Cingular won't earn much from your calls. It's a Apple-Cingular deal.

But I don't understand why Apple doesn't give developers the ability to install Javascript based widgets. From the technical side it's no difference if you have a widget or a web site with Javascript. The only difference: You have to be online for the web site.