I have the "2" version but don't know/remember what the difference is, either. I think it would be very useful for minis or folks that work with lots of fat quarters and smaller pieces of fabric. Clamping yardage down into it and then cutting what I consider normal size strips--3-5" is too much work but if I was doing a scrappy or fat quarter style quilt with the fabrics all ready cut into 1/2 yard or smaller size pieces; it is great for holding the fabric & ruler steady while you make cuts especially in multiple layers at the same time.
I bought mine to cut up scraps with but haven't actually used it for that yet. I also like all the preset angles on it. That alone makes it useful to cut wedges & triangles of all the major angle configurations and saves money on templates, specialty rulers and the confusion of flipping, flopping and twisting your regular ruler around to get the right angle.