It was time to install my vent, but I needed a 'frame' to slip it into as the siding is not flat. With a frame, I can run the siding right up to it and it'll look more polished than just cutting a hole in the siding and slapping the vent on it. The frame will also allow me to better seal the unit to prevent water intrusion. It's likely not an issue as the vent will go quite high on the popout and the top of the popout is under the deck's roof.