Camera Frame Mounts are frames that surround your camera and allow you to connect to the various Gopro-style mounts. Frame mounts like this are used when you don't need or want the full surround "waterproof" case that comes with the Gopro and SJcam.
You will find them very useful in indoor and self-stick environments, or for use in the car. They are also great if you plan to use "clip-on" style mounts. Plus, these frames are smaller and less likely to generate any attention.
TIP: Make sure the frame you choose allows you to access the power plug in AND allows to to insert and remove the MicroSD card -- not all frames have these openings!