The use of polar coordinates allows for the analysis of families of curves difficult to handle through rectangular coordinates. If a curve is the rectangular coordinate graph of a function, it cannot have any closed loops since, for a given x value there can be at most one corresponding y value. However, using polar coordinates, curves with loops can appear as graphs of functions.
In general, graphing curves in polar coordinates can be difficult and/or tedious. So, Maple can be of great assistance in this situation.