Because they were cheap I guess lol. I used the same blade for fabric and feed sacks and still they don't skip as bad as the expensive ones I got from Joann's I have had this blade in there since the day I bought the first package and its still going, thru paper feed sacks fabric all the same. Its starting to skip now after months, but the expensive ones I have had experience with since starting to quilt 12 yrs ago, would come out of package duller than the HF blades so yes they are worth it.