why dont more ppl build zzrot portal

The things a split push team's dream. 60 armor 60 mr 30% run speed while near a turret (yours or theirs, alive or dead) a portal that pushes a lane of your choice for 2 and a half minutes 2800 gold you toss this thing in a bush bot or top and the little things will start proxying your opponents lane. you want to split push but your team needs to 5 man group? get the portal bot and you all rush mid nasus wants to push top and you 4 push mid? toss the portal bot. need to distract the enemy team? portal a lane. its 2800 gold so even supports can build it, and the defence it gives is insane. GA doesnt even give that much. DID I MENTION that the little dudes scale with your defence? the item already gives 120 points of defence, and if your a tank that stacks mr/armor, you could easily get to 400-500 points. build the raptor cloak on support early on for the defence and move speed and for armor/hp5 vs their carry. its only 1k and can be build pretty much right after the sightstone. top laners or carries can build it for the raw defence it gives. its got its place in the game and i dont know why its not built way more often than it is