The functionality of the CTA buttons seems to be pretty limited. You cannot overlay an image on to the button, such as an arrow, and you cannot increase the size of the button without adding more text. In my opinion the CTA buttons should have the same functionality as the 'Divider'. It would be great to have that kind of control of the height and width of the button.
Because the main focus of this idea appears to be users wanting rounded edges we are going to close this idea as implemented. Our cross device templates do allow buttons with rounded edges through the button radius option in our editor toolbar.
In the meantime, please feel free to comment or vote on any of the other open ideas to let us know what you would like to see.