Why don't we use it as our primary package? Primarily because have thirty-plus years' worth of drawings in another format. When do we use CorelCAD? When interfacing with customers who use AutoCAD or other software that interchanges with AutoCAD. If we were starting from scratch, it would likely be our primary choice as a more economical alternative to AutoCAD with all the features most users will ever require.
CorelCAD offers a compelling and relatively low-cost solution that covers the vast majority of business needs creating both internal use drawings, drawings for fabricated parts, and creating more elaborate drawings to incorporate within CorelDraw documents.