I have found that vector and bitmap can be used to achieve many different looks. A vector can be used to get a smooth look reducing the detail of an image. It is based on points, lines and curves. A vector is basically points connected by lines of various shapes filled with color or gradient. A bitmap is used when trying to keep the details of an image. If one wants a certain look maybe if using a old image or distressed looking image then a bitmap would be appropriate to keep all of the small little details. A bitmap is constructed as an array of pixels, as it is usually used with photographs. - I used a vector for a line study to smooth out the sketchiness that the scanner produced.
After creating this vector trace it smoothed out all of the ridges and produced a smooth straight line.