Having hunted and taken antelope with both archery gear and firearms, I say, "maybe".
I think it might help a hunter to get closer, but antelope are sharp eyed and don't miss much.
I don't think it would allow a person to stalk an antelope very easily across open, flat ground, but I have little doubt it'd allow a person to peek over a ridge or bush without spooking the herd.
Used right during the "rut", it'd likely bring a dominant buck closer to run the "interloper" off, but you'd have to be at least partially concealed.
So, I think the picture of the guy kneeling in the open with his bow drawn is decieving, yet I also believe that such a "tool" might be useful in some situations.
I'd not want to use it during rifle season, with some of the idiots I've seen out "hunting" antelope.
Daryl