If you want to have your dom events be handled server-side, then it is. It also lets you do things like have a dom node be bound to the state of a server-side object so the dom contents are updated when the server-side object's contents are changed -- it just takes care of the plumbing for you.
It's possible to do, but by default Lift's form element bindings are done in a stateful way, and your session's lifetime is determined by an occasional AJAX heartbeat request. In short, while you can write applications that should work with JS disabled, you lose many things that make it awesome.
