I understand that and have used them but the stock bolts have smaller heads than most of that size and I was looking for a substitute. Cap screws with their round heads cannot be secured with those clips.
When I did the Okie assembly I ordered clips and Grade 8 bolts from a well known supplier in the Pacific Northwest. The holes in the clips were so big the bolt heads went through them. And the Grade 8 bolts? I don't think China understands that standard. These bolts looked like white metal and even had casting marks on the side.