But, most schematic capture programs are rigid and inflexible. Once a part has been loaded it's difficult to substitute a different part that is functionally equivalent. Many inexpensive schematic capture programs haven't can't do gate and pin swapping. Once you've specified 'Gate-A', you're stuck. Circuit Design creates netlists that can be read by nearly any printed circuit board layout program.
Some schematic programs are limited to a single sheet, or have ridiculously low 'pin count' limits.
The basic schematic symbols such as AND gates, Transistors and Resistors are provided and can easily be used to create specific physical devices by entering definitions in a database. And, the same database allows you to specify the template file used by your PCB program. Some programs are so complicated that you will spend countless hours just trying to figure out how it works. Object size and shape easily and individually controlled. Many editing operations can be extended to similar objects.