When I created a smallish filled circle using dc.fillCircle(x,y,17) it looked a bit "boxy", so I compared the outline with drawCircle(x,y,17):
- copying them into a drawing package ,
- overlaying one over the other as separate layers
- enlarging them to see the pixels and
- recording the image as I altered the opacity of the drawCircle.
https://youtu.be/msMzyZKLrzg
As you can see, there is a difference in the outline: the fillCircle image seems to be missing some pixels that drawCircle uses to improve the impression of a circle.
I also note that neither fill- or draw- attempt to blur the edges as the drawText does.