It's only for the player who activates it, and only if you step on the right sector or in some other way that is not console-related.
Imagine that there's a bottomless pit below you, and the only way to cross it is to use reverse gravity. People are already using reverse gravity, but one of them gets off into the save point where the gravity turns back to normal. If it was global, all the players in the ceiling would fall to the pit. Funny, but unfair to the rest of the players.