I love this little gizmo and I use it all the time.
It's a great tool for a creating a straight line or circle line track. Just drop the magnetic edge guide onto your machine bed or slide plate and it will stay in place, it can be used to set edge guides quickly. It has a strong magnet and does not move easily.
And yes, it can be used with computerized machines as long as you place it on the plate beside the presser foot and not on other parts of the machine.