The LineSpi Smart BOB is a very valuable tool when dealing with network or communication issues. It allows you to be more efficient. The LED's on the power lines gives you a quick visual on whether power and ground is at the DLC or not.
One instance was that it was missing ground on of the 2 ground lines and the scanner wouldn't communicate. Rather than stopping and trying to fix the circuit, I simply used a jumper wire and jumped pins #4 to #5 and that restored scanner communications. I was able to do my diagnostic it the vehicle without stopping to fix the circuit.
Another useful feature (optional) is the switch on Pin #16 of the DLC. This allows me to isolate the vehicle from Pin #16 of the DLC BOB. Where this is useful is when there is no power to Pin #16, I can apply power through the DLC BOB to power the scanner. Throwing the switch allows me to isolate the vehicle from my power source should there be a short on that circuit. Again, I can continue to work without having to repair the circuitry first.
Another use of the switch is when you might want to power the scanner and use the switch to isolate the vehicle to allow the vehicle's network to power down.
This product allows the use of shrouded banana plugs which a lot of scopes or meters are using.