If you use plugins from series of post about 'circle based plugins' (CreateCircle, CreateCircleSector, CreateCircleSegment etc.) or you look at source code - you will spot some drawbacks:

• new features (polygons) might be added to layer that is in Layer Panel
• duplication of code:
• creating inner and outer arc - it can be done in function
• calculation points (start and end of arc) can be done simpler (function, class)
• lack of some precondition checking:
• missing validation if radius is greater then 0, 
• missing validation if outer radius is greater then inner radius 
• missing validation if bearings from and to are not equal
•  if we have to create a lot of such polygons it would be convenient to create them in one layer and using one plugins, in which we could choose what kind of polygon we need