I agree, but it will probably never happen that all apps finally conform to what the HIG recommends about buttons. The other point is that the icons transport a sense of benign-ness of the actions and facilitate the decision of the user when he is presented a binary choice, for example. So, green, checkmark, Enter sign, et cetera always mean "go ahead", "yes", "OK", "perform the action that the dialog prompted me for" and vice versa for red, cross, etc. I can well imagine that an "Install" button goes well with that blue Enter symbol. So, until the point where there is an icon for every verb possible in a dialog[1] we should come up with a more fancy version of those old dialog-* icons. Do we always need a specific icon for a button or is a specific label enough?
[1] Install, Update, Format, Download, Connect, Rename, Publish, Convert, Build, Capture, et cetera pp ad inf. -- GTK default icons used in several places https://launchpad.net/bugs/60424 -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
