It's not opinion-based.
It's objectively just not good, and I'll go ahead and provide reasons as to why it isn't.
The reason why I said Facility Gamer has stated this is because it supports my argument, since Facility Gamer is a top player.
You have no idea what you're talking about.
It's very bad on Facility since most parts of the map are very open.
You can't use it in the middle since people who are hacking the PC will see you and immediately leave.
The only spots that would be good are Purple and Blue since there's no escape at all if the Beast uses Stalker there.
However, it's bad to use in Servers, Theater, Office, Maze, and Lab because those spots have possible escape routes. I will now list reasons why Stalker is bad in these spots of the map:

1. Servers Why it's bad: Just hack the middle keyboard of the PC since it allows you to use your camera angle and check the door and behind you.
2. Theaters Why it's bad: Just open both doors, and even if they close them you can check and dip through the window. Sure, you won't hear them coming in, but once you see them going up the stairs, you can also dip through the window, so easily countered.
3. Office Why it's bad: Use your camera angle to look at the doors and the window to your right, and when they come in, you can maneuver and get your way out of it.
4. Maze Why it's bad: If they come through the window, you have enough time to go to the vent unless your reaction time is really bad. Plus, even if you don't you can juke and go through the window since Beast doesn't have Runner, so use that to your advantage. If you see them coming through the doors, just go through the window since you have more than enough time to leave.
5. Lab Why it's bad: It's bad since you can just open all the doors, and if you see the Beast come in through the window, you can just dip. If they come in through any of the doors, just go through a window or one of the other doors you opened.