When I first started with jQuery, all I saw was simple hide/shows and effects. It really didn’t take long to figure out how to use AJAX which not only handles form submissions but it lets me take a chunk of output and use it all over my static site. Change it once and it’s updated all over.
There are a lot of plugins around for jQuery to handle a lot of routine tasks like form validation and form submission. While I started out using plugins, I’ve eventually figured out it’s just as easy to code a couple of lines and have a customized solution that you can understand and manipulate.