Unless it takes you a lot longer, reducing your material cost is always wise on the job. I don't know about the PolySteel, but I do know that for a job where you put forms up for footers, it is always wiser to use 2x12's (for example) for the forms that can later be used for floor joists (for example) than buying a bunch of 1x8s that you can't decide what to do with later. I recently did a job where 2x12s were called for floor and the total linear footage of the forms was 300. The 2x12's were later used in the floor and the savings on the job was about $500 (roughly). Your savings would be all the materials you were able to reuse. Your savings in time I disqualify from comment (sorry).
Those 2x12s by the way were also used for putting up the blocks and scaffolding, so I got a lot of mileage out of that stuff, and would always recommend it for anyone putting down full footers in Mn. (if the floor goes as low as 2x10, they'd be fine as well.