Using mustang rotors for 4.5" bc

So I'm pretty new here and I know this is kind if old but why doesn't anyone use these? I found out in my car I have this as part of a kit from this place they sell along with the KH calipers. They're already machined and come standard slotted or drilled. They work perfect on my car. Maybe I'm missing something. This is just the slotted one but if you look at the application chart it's for our cars.

What you're missing is that this mod is intended for cars that already have the KH brakes and someone wants to change over to the 4.5" bolt pattern for cheap. Mustang rotors and machine shop labor cost me less than $150. Done. Buying a new SSBC brake kit to replace everything would cost nearly $1k, with no improvement in braking.

Some folks would rather spend $150 and do a little legwork, rather than drop a grand for what amounts to basically the same brakes. Make sense?