To make it more clear.
At this time CJS is a canvas render. Which is only open space of pixel manipulate.
The text object that shouldn't be used in games so please use spritefont; is infact a DOM object of HTML5 dom rendered.... which isn't part of the canvas rendering.
So you can't mix DOM and Canvas... actually in fact the last time this question was asked I informed that TextObject because it works on the DOM layer adds a seperate rendering level on top of Canvas. This will hit your performance and games should never use DOM objects.