Why would they pay people to beta test if they can make a marketing stunt out of it? The way they did it was way smarter than to have people be beta testing behind closed doors. And also, the game is already in a pretty good condition so it makes sense to let the public play it already.
The thing with Apex legends is that they payed streamers to play their game, Riot does not(to my knowledge). So this is what people in marketing call "earned media", not "paid media".
If people will stay with the game is yet to see, the variety streamers obviously won't but I am not writing it off just yet.