Let's Cook Up Some Crown Attainments

[FallenEco]

Why not both?

Personally, it is because I subscribe to the hinted at idea that the Gate isn't an Exarch the way the others are, perhaps even being some sort of Abyssal being. The fact that it was included at all among their number feels more like a concession from the other Exarchs, rather than an acknowledgement of a peer.

But you are right, there is no reason why a different, argubly more valid version of the Gate can't have a Pralacy and Legacies devoted to it.
Though that does imply the other Exarchs should have Legacies too.

[LostLight]

Personally, it is because I subscribe to the hinted at idea that the Gate isn't an Exarch the way the others are, perhaps even being some sort of Abyssal being. The fact that it was included at all among their number feels more like a concession from the other Exarchs, rather than an acknowledgement of a peer.

But you are right, there is no reason why a different, argubly more valid version of the Gate can't have a Pralacy and Legacies devoted to it.
Though that does imply the other Exarchs should have Legacies too.

Well, I also view the Gate as somewhat.. different from the Exarchs. We could always say that Her Prelacy represents Her "Exarch visage", as being accepted to the Exarchs yet not actually being a part of them, while her Legacies represent Her more "true" nature.

[Tessie]

One does certainly not preclude the other. The Secret Order of the Gate Legacy is a cult devoted to the Gate. A Prelate of the Gate, however, is someone the Gate has taken interest in, quite possibly without the Seer necessarily wanting such attention in the first place. The two concepts can certainly overlap, but they can also serve different roles within the same game.

[KaiserAfini]

That could be interesting. The Prelate is chosen by the Gate marking their soul as an unusual result of a Paradox condition. The Secret Order of the Gate could be commanded to recruit them, independent of past alliances. But its with them that lies the secret to excisibg the Prelacy, should the chosen abhor it.

Alternatively, they could be told to guide them, with the Prelate not necessarily knowing this, but never letting them join the inner circle.

It could lead to all sorts of unique dynamics.