Apple TV can double as Home Hub device in which it records/routes to/ cloud from your cameras. Combined with high-res content, e.g. when streaming games, it can saturate the 1GbE.

Also, just learned it's still 4k 60Hz. So forget 120Hz gaming. Game streaming is likely to become a default in near future at the hardware proces we see, so limiting to 60Hz is really cheap of them at this point.