The continue_button renderer currently generates a secondary button, which de-emphasise the button. This class is intended to be used when there are mulitple options presented and the current one is low priority, so as not to distract the user from the more important options.

The use case for this renderer is you are finished on this page which wants you to read the info above and then acknowledge it with "continue" button before leaving. This almost certainly makes the button the primary call to action on the page in the many places it is used in the codebase.