Less wiring. Easier connectivity. You can't connect a DC motor directly to a gear, unless you want the robot to move 20 mph with no torque. More difficult to integrate. Few other reasons also...

Hello Dux , welcome to EZ-Robot

There are limitless options for powering a robot but the ez robot starter kit gives you everything you need to have a small robot running about in a couple hours. As you find greater needs in larger projects you only need to buy the additional parts you need. Its really great! I love the continuous servos because there are several ways to use them. Turning a torso left and right for example well beyond the normal range of the standard servo. Anyways we look forward to seeing your first robot! Please post it in your projects section so your project will show under your avatar/ profile details. It makes it easier to find and follow. Have a great day! - Josh Starnes