Div in form of button_to

Sorry if this has been mentioned elsewhere, but I couldn't find a post
about it, or an explanation in the code. I double-checked the history
and it seemed to have been that way since it was first added.

I was encountering some oddities in styling my form, and realized that
there is a redundant (especially since the form tag itself is
styleable) div created by the button_to helper. Is there some utility
to this that I am missing?