Actually, using a straight ruler and your ruler foot is easier and faster than using a walking foot for straight line quilting since you don’t have to turn the quilt and you can use the marks on the ruler to keep your spacing accurate without having to do any marking once you’ve got the first line down. I use my straight line ruler more than any of the others for ruler work.
it’s also easier to learn to use your ruler foot if you start with a straight ruler since there is a little bit of a learning curve to ruler placement since your needle is 1/4” away from the edge of the ruler, and itks also easier to learn to keep the foot against the ruler if you start with one that has a straight edge.
Rob