<p>I just got started using Adobe Flex SDK.  I was very excited because it's the first time I've found a good, <strong>free</strong> way to create Flash applications.  But then I noticed something: Flex doesn't seem to be much about making animations or designs.  It seems more like an application to build forms and menus and the like... which I can already do in (D)HTML.</p>

<p>What features does Flex have that make it better than HTML in some cases?</p>

<p>Also, are there any techniques/software programs that would allow me to add the flash/design components that I mentioned earlier?</p>

<p>Thanks!</p>

Flex, like Silverlight, is marketed for the creation of something called RIA = rich internet application. The idea being that (D)HTML isn't really well-suited to create large-scale, well-responding applications on the web. I'm not sure whether this is really (still) true but historically, it fits.
Flex and Silverlight attempt to correct this by providing two things: a different, extensible technology along with a large library and an adapted toolset for the creation of applications. The disadvantage in both cases is the dependency from further (non-free, non-standard) components. The advantage is a potentially much more productive workflow and better performance.