I think we're all going at this from the wrong direction. Obviously "sales" wants the PCI card for a "reason". Telling them why NOT isn't going to change their reason for wanting PCI.

Scott needs to find their reason and then find a better way to satisfy that need. Examples of "sales" reasons:

1) We can make a PCI card nobody else can economically supply (dongle effect).
2) If the system needs a PCI card, we can check the PC while we're installing it.
3) We can supply the PC as well, and take a markup.
4) The PC can be included in the maintenance contract.

Once you know "why" you can develop an effective "not why".