[The Chuckster]

teleporter A tier yet disguiser C tier what the hell

My line of thinking is more about it's risk to utility ratio. If someone sees you out in the open with a disguiser sniping, they know pretty much to just open fire at you. With the teleporter, while you're frozen in place for a second, you have a lot more instances where it makes sense to use it and can get you away from gunfire fast.