Yes, as above, you can use the closed toe for the quilting with 1/4" rulers. You may need the overlay, which brings the table up to the height of the foot so the ruler doesn't rock...I'm not sure with your machine, but I did with mine which is a Tiara and is the same as the Handiquilter.
The big thing about the conversion set besides allowing you the open toe is that you can change feet so you can use the couching feet and square feet and echo feet. But if you aren't into that, the original foot is just fine for ruler quilting.
Watson