I think it's a fine idea. Spine allows manipulation of drawing parameters which makes a single still image animated. This means that instead of multiple images for animating your UI, a single image fills the same needs in many cases. This also means, in almost every case, a smaller game size, which is always desirable.
One of the examples sent with your Spine installation is, in fact, an Animated title screen - Spine can serve you well in this regard.
