I use style mainly to redefine the contenttemplate to put image in the content.
For instance I create a saveStyle which have a save image in the content.
But I use style to set margin, width, height and some stuff like that too.
And with the standard toolbar the button's style don't change even if I set the style of the button.
Nevertheless, with your explanation, now I just override the contenttemplate and all works like I expect.