A:Answer The GWSSKIT has an extra USB Transmitter (similar to any of the wireless 'casting' products). Although the manual does not show a clear difference between the two products (it appears they just inserted 1 extra page showing the Receiver with the USB transmitter) but nothing about the setup. Poor documentation and showing the difference between these two products.
My guess without trying the GWSSKIT is this will allow you to wireless transmit info from IOGEAR to your TV. (My guess) The USB transmitter would be plugged into a TV's USB connector and receive info from IOGEAR transmitter...This would avoid using HDMI cable or HDMI port. But again, this is just a guess.
The GWAVRC has HDMI Cable to ties the IOGEAR A/VR directly to TV so you can mirror what ever device you have WiFi connector to the IOGEAR (phone, tablet, pc).