I think it's easier to use a walking foot for straight lines on a domestic machine. I can't imagine trying to FMQ with rulers on a domestic machine because you need both hands just to control the movement of the quilt. If you use a walking foot for straight lines, you don't need a ruler; you just need a guide -- seamline, marked line, piece of painter's tape, etc.
Rulers are more feasible on a longarm because you can control the motion of the machine with just one hand, leaving the other free to position the ruler.