It depends on what you want to use them for. Early on we had the ability to use the numbered pads around the edge as touch sensors with alligator clips, but have unfortunately run into stability and peformance problems related to that. In the interest of a stable and reliable curriculum we've disabled that feature until our engineers can get the performance under control. You can, however, use the alligator clips to connect leds, buttons, and lots of other external devices to the board. Currently we only provide block support for programming leds connected in this way, but we're working on adding more, and we do provide low level blocks that read and write to the pins.