I would like to suggest that you go to Help--Help Contents and read what it says about the Trace Bitmap tool and the VCarve toolpath. It explains how they work in detail to give you a good handle on how they work.
Many of us find it easier to draw vectors over an imported bit map rather than using the Trace Bitmap tool. YMMV
Whenever I trace a bitmap, I next use the Curve Fit-Fit curves to selected vectors--Bezier tool to clean up the tracing.
Good judgement comes from experience.
Experience comes from bad judgement.