Very useful tag indeed. Especially for non-visual browsers. But also to make the text clickable.
How could you not use this tag? It has so many intrinsic advantages - for all form elements.
Actually, the label tag is great for screen readers and other web accessibility features.
Should this tag not be used? I use this all the time, really hand and very helpful to the user.
Also, by adding on hover to the label, it provides a nice indicator that can click the text.
I use this so much, but am always suprised that everyone else doesn't.