PCIe quad PoE NIC and frame grabber

I’m trying to use 3 PoE cameras using PCIe quad PoE and I have been seeing that most of them come with a frame grabber compatibility and I was wondering if the frame grabber is necessary to have when using Poe cameras Since I’m also trying to decide if i should just use an PoE injector to hook it up to the tx2

You should be able to get more detail information from the Vendor.